👷 Docs: Testing mkdocs-material master branch

- 🐛 Updated workflow to test if `mkdocs-material` master branch commit squidfunk/mkdocs-material@a261130 by @squidfunk fixes the bug mentioned in the issue #318.

.github/workflows/deploy_docs.yml

@@ -132,7 +132,8 @@ jobs:
         if: success()
       - name: install_dependencies
         run: |
-          pip install -U mkdocs mkdocs-material mkdocs-git-revision-date-localized-plugin mkdocs-minify-plugin mkdocs-exclude mike mkdocstrings mkdocstrings-python-legacy
+          pip install -U mkdocs mkdocs-git-revision-date-localized-plugin mkdocs-minify-plugin mkdocs-exclude mike mkdocstrings mkdocstrings-python-legacy
+          pip install -U https://github.com/squidfunk/mkdocs-material/archive/a261130.zip
           pip install jinja2==3.0.*
         if: success()
       - name: git configure