MNT: Use hash for Action workflow versions and update if needed

.github/workflows/ci_tests.yml

@@ -33,11 +33,11 @@ jobs:
 
     steps:
     - name: Checkout code
-      uses: actions/checkout@v4
+      uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938  # v4.2.0
       with:
         fetch-depth: 0
     - name: Setup Miniconda
-      uses: conda-incubator/[email protected].3
+      uses: conda-incubator/setup-miniconda@a4260408e20b96e80095f42ff7f1a15b27dd94ca  # v3.0.4
       with:
         python-version: ${{ matrix.python }}
         auto-update-conda: true
@@ -51,7 +51,7 @@ jobs:
         # python -m pip install jupyter-book==0.12.1
     - name: Cache
       id: cache
-      uses: actions/cache@v4
+      uses: actions/cache@0c45773b623bea8c8e75f6c82b208c3cf94ea4f9  # v4.0.2
       with:
         path: |
           notebooks/*.fit*.bz
@@ -74,7 +74,7 @@ jobs:
         jb build .
 
     - name: Upload HTML
-      uses: actions/upload-artifact@v4
+      uses: actions/upload-artifact@50769540e7f4bd5e21e526ee35c689e35e0d6874  # v4.4.0
       with:
         name: rendered-book-sha-${{ github.sha }}
         path: |
@@ -92,12 +92,12 @@ jobs:
           if [[ "${{ github.ref }}" == 'refs/heads/main' ]]; then VERSION_NUMBER=dev; fi
           echo "VERSION_NUMBER=$VERSION_NUMBER" >> $GITHUB_ENV
       - name: Download artifact
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16  # v4.1.8
         with:
           name: rendered-book-sha-${{ github.sha }}
           path: dev
       - name: Deploy pages
-        uses: peaceiris/actions-gh-pages@v4
+        uses: peaceiris/actions-gh-pages@4f9cc6602d3f66b9c108549d475ec49e8ef4d45e  # v4.0.0
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           publish_dir: dev