Fix sphinx workflow to clone gh-pages from rai-opensource, not petercorke (#205)

Author: petercorke

.github/workflows/sphinx.yml

@@ -29,7 +29,7 @@ jobs:
         cd ../
     - name: Commit documentation changes
       run: |
-        git clone https://github.com/petercorke/spatialmath-python.git --branch gh-pages --single-branch gh-pages
+        git clone https://github.com/${{ github.repository }}.git --branch gh-pages --single-branch gh-pages
         cp -r docs/build/html/* gh-pages/
         cd gh-pages
         git config --local user.email "action@github.com"