GitHub actions: use frozen list of Python packages

.github/workflows/sphinx-books-tests.js.yml

@@ -61,7 +61,7 @@ jobs:
     - name: Install Python dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install -r requirements.txt
+        pip install -r requirements_frozen.txt
     - name: Run Webpack production
       run: make cleanall webpack-production
     - name: Run SPHINX content tests

.github/workflows/sphinx-content-tests.js.yml

@@ -50,7 +50,7 @@ jobs:
     - name: Install Python dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install -r requirements.txt
+        pip install -r requirements_frozen.txt
     - name: Run SPHINX engine tests
       run: make SPHINXOPTS="-W" test_engine
     - name: Build HTML content

.github/workflows/sphinx-plugin-tests.js.yml

@@ -43,6 +43,6 @@ jobs:
     - name: Install Python dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install -r requirements.txt
+        pip install -r requirements_frozen.txt
     - name: Test Sphinx Widget Parser Plugin
       run: make test_parser

.github/workflows/typescript-tests.js.yml

@@ -55,7 +55,7 @@ jobs:
     - name: Install Python dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install -r requirements.txt
+        pip install -r requirements_frozen.txt
     - name: Build HTML test pages
       run: make site-testing
     - name: Run Typescript tests