adding a apt-get update

Author: jonathan-taylor

.github/workflows/build_docs.yml

@@ -28,6 +28,7 @@ jobs: # This workflow contains a single
       # Install
       - name: Install dependencies 
         run: |
+          sudo apt-get update
           sudo apt-get install -y r-base libtirpc-dev
           pip install -r docs/requirements.txt
           pip install .