Change CI to push to cpp-docs branch

.github/workflows/doxygen.yml

@@ -37,7 +37,8 @@ jobs:
       run: |
         git config --global user.name "${{ env.CI_COMMIT_AUTHOR }}"
         git config --global user.email "[email protected]"
-        git add -f  docs
+        git checkout cpp-docs
+        git add doc
         git commit -m "${{ env.CI_COMMIT_MESSAGE }}"
         git push