add github workflow to push buf.build definitions

.github/workflows/buf.yml

@@ -0,0 +1,43 @@
+name: Buf
+
+on:
+  pull_request:
+  push:
+    tags:
+      - v*
+    branches:
+      - develop
+      - release/v*
+      - feature/*
+
+jobs:
+  buf:
+    runs-on: ubuntu-20.04
+    permissions:
+      contents: read
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Setup buf
+        uses: bufbuild/buf-setup-action@v1
+
+      - name: Lint protos
+        # TODO: Consider enabling this after fixing or ignoring the current linting errors?
+        if: false
+        uses: bufbuild/buf-lint-action@v1
+
+      - name: Check for breaking changes
+        if: github.event_name == 'pull_request'
+        uses: bufbuild/buf-breaking-action@v1
+        with:
+          input: proto
+          against: 'https://github.com/${{ github.repository }}.git#branch=${{ github.base_ref }}'
+
+      - uses: bufbuild/buf-push-action@v1
+        if: github.event_name != 'pull_request'
+        with:
+          input: proto
+          buf_token: ${{ secrets.BUF_TOKEN }}
+          draft: ${{ !startsWith(github.ref, 'refs/tags/v') }}