Apply suggestions from code review

.github/workflows/sphinx.yml

@@ -14,8 +14,8 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/setup-python@0b93645e9fea7318ecaed2b359559ac225c90a2b # v5.3.0
         with:
           python-version: "3.x"
           architecture: "x64"
@@ -26,7 +26,7 @@ jobs:
           pip install -r docs/requirements.txt  # redundant?
           make html
       - name: Upload artifact
-        uses: actions/upload-pages-artifact@v3
+        uses: actions/upload-pages-artifact@56afc609e74202658d3ffba0e8f6dda462b719fa # v3.0.1
         with:
           # Upload entire repository
           path: 'build/html'
@@ -50,4 +50,4 @@ jobs:
     steps:
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v4
+        uses: actions/deploy-pages@d6db90164ac5ed86f2b6aed7e0febac5b3c0c03e # v4.0.5

.github/workflows/tests.yml

@@ -18,7 +18,7 @@ jobs:
         python-version: [3.8, 3.9, '3.10', 3.11, 3.12]
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
 
     - name: Additional info about the build
       shell: bash
@@ -29,7 +29,7 @@ jobs:
 
 
     # More info on options: https://github.com/conda-incubator/setup-miniconda
-    - uses: conda-incubator/setup-miniconda@v3
+    - uses: conda-incubator/setup-miniconda@d2e6a045a86077fb6cad6f5adf368e9076ddaa8d # v3.1.0
       with:
         python-version: ${{ matrix.python-version }}
         environment-file: devtools/conda-envs/test_env.yaml