template: Simplify job matrix

We are currently not using the distinction between "os" and "arch", and
only using both to construct the `runs-on:` string. This makes things
much more complicated than necessary, so this commit updates the matrix
to use a single 'platform' key that we can use directly in `runs-on`.

Signed-off-by: Leandro Lucarella <luca-frequenz@llucax.com>

Author: llucax

cookiecutter/{{cookiecutter.github_repo_name}}/.github/workflows/ci.yaml

@@ -61,11 +61,9 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        arch:
-          - amd64
-          - arm
-        os:
+        platform:
           - ubuntu-24.04
+          - ubuntu-24.04-arm
         python:
           - "3.11"
           - "3.12"
@@ -74,7 +72,7 @@ jobs:
           # that uses the same venv to run multiple linting sessions
           - "ci_checks_max"
           - "pytest_min"
-    runs-on: ${{ matrix.os }}${{ matrix.arch != 'amd64' && format('-{0}', matrix.arch) || '' }}
+    runs-on: ${{ matrix.platform }}
 
     steps:
       - name: Run nox
@@ -145,15 +143,13 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        arch:
-          - amd64
-          - arm
-        os:
+        platform:
           - ubuntu-24.04
+          - ubuntu-24.04-arm
         python:
           - "3.11"
           - "3.12"
-    runs-on: ${{ matrix.os }}${{ matrix.arch != 'amd64' && format('-{0}', matrix.arch) || '' }}
+    runs-on: ${{ matrix.platform }}
 
     steps:
       - name: Setup Git

tests_golden/integration/test_cookiecutter_generation/actor/frequenz-actor-test/.github/workflows/ci.yaml

@@ -28,11 +28,9 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        arch:
-          - amd64
-          - arm
-        os:
+        platform:
           - ubuntu-24.04
+          - ubuntu-24.04-arm
         python:
           - "3.11"
           - "3.12"
@@ -41,7 +39,7 @@ jobs:
           # that uses the same venv to run multiple linting sessions
           - "ci_checks_max"
           - "pytest_min"
-    runs-on: ${{ matrix.os }}${{ matrix.arch != 'amd64' && format('-{0}', matrix.arch) || '' }}
+    runs-on: ${{ matrix.platform }}
 
     steps:
       - name: Run nox
@@ -112,15 +110,13 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        arch:
-          - amd64
-          - arm
-        os:
+        platform:
           - ubuntu-24.04
+          - ubuntu-24.04-arm
         python:
           - "3.11"
           - "3.12"
-    runs-on: ${{ matrix.os }}${{ matrix.arch != 'amd64' && format('-{0}', matrix.arch) || '' }}
+    runs-on: ${{ matrix.platform }}
 
     steps:
       - name: Setup Git

tests_golden/integration/test_cookiecutter_generation/api/frequenz-api-test/.github/workflows/ci.yaml

@@ -58,11 +58,9 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        arch:
-          - amd64
-          - arm
-        os:
+        platform:
           - ubuntu-24.04
+          - ubuntu-24.04-arm
         python:
           - "3.11"
           - "3.12"
@@ -71,7 +69,7 @@ jobs:
           # that uses the same venv to run multiple linting sessions
           - "ci_checks_max"
           - "pytest_min"
-    runs-on: ${{ matrix.os }}${{ matrix.arch != 'amd64' && format('-{0}', matrix.arch) || '' }}
+    runs-on: ${{ matrix.platform }}
 
     steps:
       - name: Run nox
@@ -142,15 +140,13 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        arch:
-          - amd64
-          - arm
-        os:
+        platform:
           - ubuntu-24.04
+          - ubuntu-24.04-arm
         python:
           - "3.11"
           - "3.12"
-    runs-on: ${{ matrix.os }}${{ matrix.arch != 'amd64' && format('-{0}', matrix.arch) || '' }}
+    runs-on: ${{ matrix.platform }}
 
     steps:
       - name: Setup Git

tests_golden/integration/test_cookiecutter_generation/app/frequenz-app-test/.github/workflows/ci.yaml

@@ -28,11 +28,9 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        arch:
-          - amd64
-          - arm
-        os:
+        platform:
           - ubuntu-24.04
+          - ubuntu-24.04-arm
         python:
           - "3.11"
           - "3.12"
@@ -41,7 +39,7 @@ jobs:
           # that uses the same venv to run multiple linting sessions
           - "ci_checks_max"
           - "pytest_min"
-    runs-on: ${{ matrix.os }}${{ matrix.arch != 'amd64' && format('-{0}', matrix.arch) || '' }}
+    runs-on: ${{ matrix.platform }}
 
     steps:
       - name: Run nox
@@ -112,15 +110,13 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        arch:
-          - amd64
-          - arm
-        os:
+        platform:
           - ubuntu-24.04
+          - ubuntu-24.04-arm
         python:
           - "3.11"
           - "3.12"
-    runs-on: ${{ matrix.os }}${{ matrix.arch != 'amd64' && format('-{0}', matrix.arch) || '' }}
+    runs-on: ${{ matrix.platform }}
 
     steps:
       - name: Setup Git

tests_golden/integration/test_cookiecutter_generation/lib/frequenz-test-python/.github/workflows/ci.yaml

@@ -28,11 +28,9 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        arch:
-          - amd64
-          - arm
-        os:
+        platform:
           - ubuntu-24.04
+          - ubuntu-24.04-arm
         python:
           - "3.11"
           - "3.12"
@@ -41,7 +39,7 @@ jobs:
           # that uses the same venv to run multiple linting sessions
           - "ci_checks_max"
           - "pytest_min"
-    runs-on: ${{ matrix.os }}${{ matrix.arch != 'amd64' && format('-{0}', matrix.arch) || '' }}
+    runs-on: ${{ matrix.platform }}
 
     steps:
       - name: Run nox
@@ -112,15 +110,13 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        arch:
-          - amd64
-          - arm
-        os:
+        platform:
           - ubuntu-24.04
+          - ubuntu-24.04-arm
         python:
           - "3.11"
           - "3.12"
-    runs-on: ${{ matrix.os }}${{ matrix.arch != 'amd64' && format('-{0}', matrix.arch) || '' }}
+    runs-on: ${{ matrix.platform }}
 
     steps:
       - name: Setup Git

tests_golden/integration/test_cookiecutter_generation/model/frequenz-model-test/.github/workflows/ci.yaml

@@ -28,11 +28,9 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        arch:
-          - amd64
-          - arm
-        os:
+        platform:
           - ubuntu-24.04
+          - ubuntu-24.04-arm
         python:
           - "3.11"
           - "3.12"
@@ -41,7 +39,7 @@ jobs:
           # that uses the same venv to run multiple linting sessions
           - "ci_checks_max"
           - "pytest_min"
-    runs-on: ${{ matrix.os }}${{ matrix.arch != 'amd64' && format('-{0}', matrix.arch) || '' }}
+    runs-on: ${{ matrix.platform }}
 
     steps:
       - name: Run nox
@@ -112,15 +110,13 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        arch:
-          - amd64
-          - arm
-        os:
+        platform:
           - ubuntu-24.04
+          - ubuntu-24.04-arm
         python:
           - "3.11"
           - "3.12"
-    runs-on: ${{ matrix.os }}${{ matrix.arch != 'amd64' && format('-{0}', matrix.arch) || '' }}
+    runs-on: ${{ matrix.platform }}
 
     steps:
       - name: Setup Git