feat(ci): trigger a workflow for reviewing patches (#12277)

This commit adds a workflow that opens a companion PR (the link being displayed as mentioning current PR) when developer
opens a PR that modifies openresty patches.

The companion PR automatically creates and updates
in-place when the PR at kong or kong-ee updates, and displays only the diffs for patches files to help reviewer
understand the changes better.

.github/workflows/openresty-patches-companion.yml

@@ -0,0 +1,20 @@
+name: Openresty patches review companion
+on:
+  pull_request:
+    paths:
+    - 'build/openresty/patches/**'
+
+jobs:
+  create-pr:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Dispatch the workflow
+        uses: benc-uk/workflow-dispatch@798e70c97009500150087d30d9f11c5444830385 # v1
+        with:
+          workflow: create-pr.yml
+          repo: kong/openresty-patches-review
+          ref: master
+          token: ${{ secrets.PAT }}
+          inputs: |
+            {"pr-branch":"${{ github.event.pull_request.head.repo.owner.login }}:${{ github.head_ref }}", "pr-base":"${{ github.base_ref }}", "ee":${{ contains(github.repository, 'kong-ee') && 'true' || 'false' }}, "pr-id":"${{ github.event.pull_request.number }}"}
+