Hash pin GitHub Actions and add cooldown to Dependabot

.github/dependabot.yml

@@ -10,3 +10,8 @@ updates:
       actions:
         patterns:
           - "*"
+    cooldown:
+      # https://blog.yossarian.net/2025/11/21/We-should-all-be-using-dependency-cooldowns
+      # Cooldowns protect against supply chain attacks by avoiding the
+      # highest-risk window immediately after new releases.
+      default-days: 14

.github/workflows/lint.yml

@@ -13,10 +13,10 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           persist-credentials: false
-      - uses: actions/setup-python@v6
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: "3.x"
-      - uses: tox-dev/action-pre-commit-uv@v1
+      - uses: tox-dev/action-pre-commit-uv@246b66536e366bb885f52d61983bf32f7c95e8b1 # 1.0.3

.github/workflows/release.yml

@@ -21,12 +21,12 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           fetch-depth: 0
           persist-credentials: false
 
-      - uses: hynek/build-and-inspect-python-package@v2
+      - uses: hynek/build-and-inspect-python-package@fe0a0fb1925ca263d076ca4f2c13e93a6e92a33e # v2.17.0
 
   # Publish to Test PyPI on every commit on main.
   release-test-pypi:
@@ -43,13 +43,13 @@ jobs:
 
     steps:
       - name: Download packages built by build-and-inspect-python-package
-        uses: actions/download-artifact@v8
+        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
         with:
           name: Packages
           path: dist
 
       - name: Publish to Test PyPI
-        uses: pypa/gh-action-pypi-publish@release/v1
+        uses: pypa/gh-action-pypi-publish@cef221092ed1bacb1cc03d23a2d87d1d172e277b # v1.14.0
         with:
           repository-url: https://test.pypi.org/legacy/
 
@@ -75,10 +75,10 @@ jobs:
 
     steps:
       - name: Download packages built by build-and-inspect-python-package
-        uses: actions/download-artifact@v8
+        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
         with:
           name: Packages
           path: dist
 
       - name: Publish to PyPI
-        uses: pypa/gh-action-pypi-publish@release/v1
+        uses: pypa/gh-action-pypi-publish@cef221092ed1bacb1cc03d23a2d87d1d172e277b # v1.14.0

.github/workflows/test.yml

@@ -17,25 +17,25 @@ jobs:
         python-version: ["3.10", "3.11", "3.12", "3.13", "3.14", "3.15"]
 
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           persist-credentials: false
 
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v6
+        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: ${{ matrix.python-version }}
           allow-prereleases: true
 
       - name: Install uv
-        uses: hynek/setup-cached-uv@v2
+        uses: hynek/setup-cached-uv@4300ec2180bc77d705e626a34e381b81a4772c51 # v2.5.0
 
       - name: Tox tests
         run: |
           uvx --with tox-uv tox -e py
 
       - name: Upload coverage
-        uses: codecov/codecov-action@v6
+        uses: codecov/codecov-action@57e3a136b779b570ffcdbf80b3bdc90e7fab3de2 # v6.0.0
         with:
           flags: ${{ matrix.python-version }}
           name: Python ${{ matrix.python-version }}