Update deploy_docs.yml

.github/workflows/deploy_docs.yml

@@ -20,6 +20,7 @@ jobs:
         python -m pip install --upgrade pip
         pip install boto smart_open sphinx sphinx-rtd-theme pythainlp
         pip install -e .
+        if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
     - name: Build sphinx documentation
       run: |
         cd docs && make html