Add poetry checks workflow extracted from make-base-ci

This workflow checks for changes in poetry.lock on pull requests targeting the main branch.

Author: banginji

.github/workflows/poetry-checks.yml

@@ -0,0 +1,30 @@
+name: poetry checks
+
+on:
+  pull_request_target:
+    branches: [ "main" ]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request_target.number || github.ref }}
+  cancel-in-progress: true
+
+permissions: {}
+
+jobs:
+  diff-poetry-lock:
+    # FIXME: Remove when https://github.com/target/make-python-devex/issues/119 is fixed
+    continue-on-error: true
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+      issues: write
+      contents: read
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+      with:
+        persist-credentials: false
+    # This will post a comment on PRs when poetry.lock changes
+    - name: Diff poetry.lock
+      uses: colindean/diff-poetry-lock@nl
+