ci: pin third-party actions to commit SHAs

Replace tag references (@v4, @v5, @release/v1, ...) with the
corresponding commit SHA, keeping the tag in a trailing comment so
the human-readable version is still visible. This protects CI from
an upstream tag being moved to point at different code than what we
last reviewed.

The ably/features reusable workflow reference is left on @main on
purpose, since that's an internal Ably workflow.

Author: emptyhammond

.github/workflows/check.yml

@@ -23,22 +23,22 @@ jobs:
       matrix:
         python-version: ['3.8', '3.9', '3.10', '3.11', '3.12', '3.13', '3.14']
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           submodules: 'recursive'
           persist-credentials: false
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5
         id: setup-python
         with:
           python-version: ${{ matrix.python-version }}
 
       - name: Install uv
-        uses: astral-sh/setup-uv@v7
+        uses: astral-sh/setup-uv@37802adc94f370d6bfd71619e3f0bf239e1f3b78 # v7
         with:
           enable-cache: true
 
-      - uses: actions/cache@v4
+      - uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830 # v4
         name: Define a cache for the virtual environment based on the dependencies lock file
         id: cache
         with:

.github/workflows/lint.yml

@@ -14,22 +14,22 @@ jobs:
       contents: read
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           submodules: 'recursive'
           persist-credentials: false
       - name: Set up Python 3.9
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5
         id: setup-python
         with:
           python-version: '3.9'
 
       - name: Install uv
-        uses: astral-sh/setup-uv@v7
+        uses: astral-sh/setup-uv@37802adc94f370d6bfd71619e3f0bf239e1f3b78 # v7
         with:
           enable-cache: true
 
-      - uses: actions/cache@v4
+      - uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830 # v4
         name: Define a cache for the virtual environment based on the dependencies lock file
         id: cache
         with:

.github/workflows/release.yml

@@ -16,18 +16,18 @@ jobs:
       contents: read
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           submodules: 'recursive'
           persist-credentials: false
       - name: Set up Python 3.12
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5
         id: setup-python
         with:
           python-version: 3.12
 
       - name: Install uv
-        uses: astral-sh/setup-uv@v7
+        uses: astral-sh/setup-uv@37802adc94f370d6bfd71619e3f0bf239e1f3b78 # v7
         with:
           enable-cache: false
 
@@ -38,7 +38,7 @@ jobs:
       - name: Build a binary wheel and a source tarball
         run: uv build
       - name: Store the distribution packages
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
         with:
           name: python-package-distributions
           path: dist/
@@ -80,7 +80,7 @@ jobs:
 
     steps:
       - name: Download all the dists
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4
         with:
           name: python-package-distributions
           path: dist/
@@ -108,7 +108,7 @@ jobs:
           TAG: ${{ steps.tag.outputs.tag }}
 
       - name: Publish distribution 📦 to PyPI
-        uses: pypa/gh-action-pypi-publish@release/v1
+        uses: pypa/gh-action-pypi-publish@cef221092ed1bacb1cc03d23a2d87d1d172e277b # release/v1
 
   publish-to-testpypi:
     name: Publish Python distribution to TestPyPI
@@ -125,11 +125,11 @@ jobs:
 
     steps:
       - name: Download all the dists
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4
         with:
           name: python-package-distributions
           path: dist/
       - name: Publish distribution 📦 to TestPyPI
-        uses: pypa/gh-action-pypi-publish@release/v1
+        uses: pypa/gh-action-pypi-publish@cef221092ed1bacb1cc03d23a2d87d1d172e277b # release/v1
         with:
           repository-url: https://test.pypi.org/legacy/