fix sphinx build dependencies – sphinxcontrib-youtube

Author: pavelnikonorov

.github/workflows/documentation.yaml

@@ -8,7 +8,7 @@ jobs:
       - uses: actions/setup-python@v3
       - name: Install dependencies
         run: |
-          pip install sphinx sphinx_rtd_theme
+          pip install sphinx sphinx_rtd_theme sphinxcontrib-youtube
       - name: Sphinx build
         run: |
           sphinx-build docs _build