ci: add GitHub token to buf-setup-action to avoid API rate limits

The buf-setup-action was hitting GitHub API rate limits for unauthenticated
requests. Adding the GITHUB_TOKEN allows authenticated requests which have
a much higher rate limit.

Author: adityamaru

.github/workflows/build.yaml

@@ -19,6 +19,8 @@ jobs:
 
       - name: Setup Buf
         uses: bufbuild/buf-setup-action@v1
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Configure Buf Registry
         run: |