use internal release_open_source.py script to commit changes and create PR (#29686)

tools/distrib/docgen/all_lang_docgen.sh

@@ -62,7 +62,7 @@ cd "${dir}/../../.."
 # Clones the API reference GitHub Pages branch
 PAGES_PATH="/tmp/gh-pages"
 rm -rf "${PAGES_PATH}"
-git clone --single-branch https://github.com/grpc/grpc -b gh-pages "${PAGES_PATH}"
+git clone -o upstream --single-branch https://github.com/grpc/grpc -b gh-pages "${PAGES_PATH}"
 
 # Generates Core / C++ / ObjC / PHP documents
 rm -rf "${PAGES_PATH}/core" "${PAGES_PATH}/cpp" "${PAGES_PATH}/objc" "${PAGES_PATH}/php"
@@ -91,20 +91,4 @@ echo "================================================================="
 echo "  Successfully generated documents for version ${GRPC_VERSION}."
 echo "================================================================="
 
-# Uploads to GitHub
-if [[ -n "${GITHUB_USER}" ]]; then
-    BRANCH_NAME="doc-${GRPC_VERSION}"
-
-    (cd "${PAGES_PATH}"
-        git remote add "${GITHUB_USER}" "git@github.com:${GITHUB_USER}/grpc.git"
-        git checkout -b "${BRANCH_NAME}"
-        git add --all
-        git commit -m "Auto-update documentation for gRPC ${GRPC_VERSION}"
-        git push --set-upstream "${GITHUB_USER}" "${BRANCH_NAME}"
-    )
-
-    echo "Please check https://github.com/${GITHUB_USER}/grpc/tree/${BRANCH_NAME} for generated documents."
-    echo "Click https://github.com/grpc/grpc/compare/gh-pages...${GITHUB_USER}:${BRANCH_NAME} to create a PR."
-else
-    echo "Please check ${PAGES_PATH} for generated documents."
-fi
+echo "Generated docs are in ${PAGES_PATH}, use the internal release script to create a PR."