ci: add concurrency groups to cancel superseded PR runs (#182)

A new push to a PR branch now cancels the in-progress run for that ref across the
seven test-* workflows (pull_request events only; main pushes always finish).
Frees runner slots and speeds feedback.

Author: reuvenharrison

.github/workflows/test-breaking.yaml

@@ -3,6 +3,10 @@ on:
   push:
     branches: [main]
   pull_request:
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 jobs:
   oasdiff_breaking:
     runs-on: ubuntu-latest

.github/workflows/test-changelog.yaml

@@ -3,6 +3,10 @@ on:
   push:
     branches: [main]
   pull_request:
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 jobs:
   oasdiff_changelog:
     runs-on: ubuntu-latest

.github/workflows/test-diff.yaml

@@ -3,6 +3,10 @@ on:
   push:
     branches: [main]
   pull_request:
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 jobs:
   oasdiff_diff:
     runs-on: ubuntu-latest

.github/workflows/test-error-annotation.yaml

@@ -3,6 +3,10 @@ on:
   push:
     branches: [main]
   pull_request:
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 jobs:
   entrypoint_error_annotation:
     runs-on: ubuntu-latest

.github/workflows/test-pr-comment.yaml

@@ -3,6 +3,10 @@ on:
   push:
     branches: [main]
   pull_request:
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 jobs:
   pr_comment_tolerates_oasdiff_fail_on:
     runs-on: ubuntu-latest

.github/workflows/test-validate.yaml

@@ -3,6 +3,10 @@ on:
   push:
     branches: [main]
   pull_request:
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 jobs:
   oasdiff_validate_valid:
     runs-on: ubuntu-latest

.github/workflows/test-verify.yaml

@@ -4,6 +4,10 @@ on:
     branches: [main]
   pull_request:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 jobs:
   verify_all_green:
     runs-on: ubuntu-latest