ci: ReadTheDocs deploy demo

Author: attakei

.readthedocs.yaml

@@ -6,7 +6,8 @@ build:
     python: '3.12'
   commands:
     - pip install uv
-    - uv sync --frozen
+    - uv sync --frozen --all-extras
+    - uv run mkdocs build
     - uv run sphinx-apidoc -f -e -T -o=docs/api/ ./oembedpy
     - uv run sphinx-build -b dirhtml docs $READTHEDOCS_OUTPUT/html