feature(ci): protobuf compatibility check (pt 2) (#18553)

* buf workspace config

* remove ignore dir

* add workflow

* update action versions

* correct repo

* temporarily remove proto.yml

* feature(ci): protobuf compatibility check pt 2

* example proto change

* example compatible change

* revert proto file

* change ref branch to master

* fmt

.github/workflows/protobuf.yml

@@ -0,0 +1,27 @@
+name: Protobuf Compatibility
+
+on:
+  pull_request:
+    paths:
+        - "proto/**"
+        - "lib/vector-core/proto/**"
+  merge_group:
+    types: [checks_requested]
+
+concurrency:
+    # `github.event.number` exists for pull requests, otherwise fall back to SHA for merge queue
+    group: ${{ github.workflow }}-${{ github.event.number || github.event.merge_group.head_sha }}
+    cancel-in-progress: true
+
+jobs:
+  validate-protos:
+    runs-on: ubuntu-latest
+    steps:
+      # Run `git checkout`
+      - uses: actions/checkout@v3
+      # Install the `buf` CLI
+      - uses: bufbuild/buf-setup-action@v1.26.1
+      # Perform breaking change detection against the `master` branch
+      - uses: bufbuild/buf-breaking-action@v1.1.3
+        with:
+          against: "https://github.com/vectordotdev/vector.git#branch=master"