Simplify build docs step

Author: hmakelin

.github/workflows/build_and_deploy_sphinx_docs.yml

@@ -13,15 +13,14 @@ on:
 jobs:
   build:
     runs-on: ubuntu-20.04
+    container: ghcr.io/${{ github.repository }}:latest
     defaults:
       run:
         shell: bash
     steps:
       - name: Build Sphinx docs
         run: |
-          mkdir docs
-          docker run ghcr.io/${{ github.repository }}:latest bash -c "cd /opt/colcon_ws/src/gisnav && make docs"
-          docker cp $(docker ps -q -l):/opt/colcon_ws/src/gisnav/docs/_build docs
+          make docs
 
       - name: Install node
         run: |