Pin GHA workflows and add dependabot to keep them up to date

.github/dependabot.yml

@@ -0,0 +1,11 @@
+version: 2
+updates:
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly
+    ignore:
+      # Ignore all patch releases as we can manually
+      # upgrade if we run into a bug and need a fix.
+      - dependency-name: "*"
+        update-types: ["version-update:semver-patch"]

.github/workflows/codeql-analysis.yml

@@ -32,7 +32,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v2
+      uses: actions/checkout@ee0669bd1cc54295c223e0bb666b733df41de1c5 # v2.7.0
       with:
         # We must fetch at least the immediate parents so that if this is
         # a pull request then we can checkout the head.
@@ -45,7 +45,7 @@ jobs:
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL
-      uses: github/codeql-action/init@v1
+      uses: github/codeql-action/init@231aa2c8a89117b126725a0e11897209b7118144 # v1.1.39
       with:
         languages: "python"
         # If you wish to specify custom queries, you can do so here or in a config file.
@@ -56,7 +56,7 @@ jobs:
     # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
     # If this step fails, then you should remove it and run the build manually (see below)
     - name: Autobuild
-      uses: github/codeql-action/autobuild@v1
+      uses: github/codeql-action/autobuild@231aa2c8a89117b126725a0e11897209b7118144 # v1.1.39
 
     # ℹ️ Command-line programs to run using the OS shell.
     # 📚 https://git.io/JvXDl
@@ -70,4 +70,4 @@ jobs:
     #   make release
 
     - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@v1
+      uses: github/codeql-action/analyze@231aa2c8a89117b126725a0e11897209b7118144 # v1.1.39

.github/workflows/lint.yml

@@ -11,10 +11,10 @@ jobs:
     timeout-minutes: 10
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
     - name: Set up Python
-      uses: actions/setup-python@v4
+      uses: actions/setup-python@61a6322f88396a6271a6ee3565807d608ecaddd1 # v4.7.0
       with:
         python-version: "3.x"
     - name: Run pre-commit
-      uses: pre-commit/[email protected]
+      uses: pre-commit/action@646c83fcd040023954eafda54b4db0192ce70507 # v3.0.0

.github/workflows/lock-issues.yml

@@ -13,7 +13,7 @@ jobs:
     if: github.repository_owner == 'psf'
     runs-on: ubuntu-latest
     steps:
-      - uses: dessant/lock-threads@v3
+      - uses: dessant/lock-threads@e460dfeb36e731f3aeb214be6b0c9a9d9a67eda6 # v3.0.0
         with:
             issue-lock-inactive-days: 90
             pr-lock-inactive-days: 90

.github/workflows/run-tests.yml

@@ -21,9 +21,9 @@ jobs:
             os: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@ee0669bd1cc54295c223e0bb666b733df41de1c5 # v2.7.0
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@e9aba2c848f5ebd159c070c61ea2c4e2b122355e # v2.3.4
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies