Authenticate proto download in CI to sidestep rate limit (#491)

Author: nipunn1313

.github/workflows/main.yml

@@ -120,6 +120,7 @@ jobs:
         uses: arduino/setup-protoc@v1
         with:
           version: "${{ steps.read_versions.outputs.PROTOBUF_VERSION }}"
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
       - name: Run Protoc
         run: |
           pip3 install -e .