fix(docs): install requirements CORRECTLY in CI (#224)

Signed-off-by: Max SCHMELLER <[email protected]>

.github/workflows/documentation.yml

@@ -34,7 +34,7 @@ jobs:
           Jinja2 \
           ruamel.yaml && \
           pip install git+https://github.com/JakubAndrysek/mkdoxy && \
-          pip install docs/requirements.txt
+          pip install -r docs/requirements.txt
       - run: mkdocs build --site-dir _site
       - run: touch _site/.nojekyll
       - run: |