docs: define mkdocs dependencies in requirements-mkdocs.txt

.github/workflows/main.yml

@@ -13,7 +13,5 @@ jobs:
       - uses: actions/setup-python@v2
         with:
           python-version: 3.x
-      - run: pip install mkdocs-material
-      - run: pip install mkdocs-redirects
-      - run: pip install mkdocs-git-revision-date-localized-plugin
+      - run: pip3 install -r requirements-mkdocs.txt
       - run: mkdocs gh-deploy --force

docs/Developers/index.md

@@ -4,10 +4,9 @@
 
 Documentation is is written as markdown, processed using mkdocs ([docs](https://www.mkdocs.org/user-guide/writing-your-docs/#writing-your-docs)) and the Material theme ([docs](https://squidfunk.github.io/mkdocs-material/reference/)). The Material theme is not just styling, but provides additional syntax extensions.
 
-Setup your system for Material:
+Setup your system for mkdocs and Material:
 ```
-pip3 install mkdocs-material
-pip3 install mkdocs-git-revision-date-localized-plugin
+pip3 install -r requirements-mkdocs.txt
 ```
 
 To test your local changes while writing them and before making a pull-request:

requirements-mkdocs.txt

@@ -0,0 +1,3 @@
+mkdocs-material
+mkdocs-material-extensions
+mkdocs-redirects