add gh action buildkite

Author: tudor

.github/workflows/trigger_buildkite_build.yml

@@ -0,0 +1,25 @@
+name: Trigger BuildKite build of Docker image for building PGlite
+
+on:
+  push:
+    branches: ['pglite/REL_16_STABLE']
+    paths:
+      - pglite/.buildconfig
+  pull_request:
+    paths:
+      - pglite/.buildconfig
+
+jobs:
+  build:
+    name: Build Docker image
+    runs-on: ubuntu-22.04
+    steps:
+      - name: Trigger a Buildkite Build on Push using v2.0.0
+        uses: buildkite/trigger-pipeline-action@v2.0.0
+        with:
+          buildkite_api_access_token: ${{ secrets.TRIGGER_BK_BUILD_TOKEN }}
+          pipeline: 'vaxine/build-pglite-builder-docker-image'
+          branch: ${{ github.head_ref || github.ref_name }}
+          commit: HEAD
+          message: '🚀 Triggered from a GitHub Action'
+          build_env_vars: '{"TRIGGERED_FROM_GHA": "true"}'