add faiss to wkflow file

.github/workflows/docs.yml

@@ -23,6 +23,7 @@ jobs:
       # ADJUST THIS: install all dependencies (including pdoc)
       - run: pip install pdoc3
       - run: pip install -e .
+      - run: pip install faiss
       - run: python -m spacy download en_core_web_sm
       # ADJUST THIS: build your documentation into docs/.
       # We use a custom build script for pdoc itself, ideally you just run `pdoc -o docs/ ...` here.