Aktualisieren Dockerfile

Dockerfile

+FROM: python:3.8-buster
+
+# Documentation static site generator & deployment tool
+RUN pip install mkdocs>=1.1.2
+
+# Add custom theme if not inside a theme_dir
+# (https://github.com/mkdocs/mkdocs/wiki/MkDocs-Themes)
+RUN pip install mkdocs-material>=5.4.0