ci: Add workflow to check PR description has been filled (#6965)

.github/workflows/check-pr-description.yml

@@ -0,0 +1,30 @@
+name: Check PR description
+
+on:
+  merge_group:
+    types:
+      - checks_requested
+  pull_request:
+    types: [opened, edited, reopened, synchronize, ready_for_review]
+    branches: [develop]
+
+jobs:
+  check_description:
+    if: ${{ github.event.pull_request.draft != true }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+
+      - name: Write PR body to file
+        env:
+          PR_BODY: ${{ github.event.pull_request.body }}
+        if: ${{ github.event_name == 'pull_request' }}
+        run: printenv PR_BODY > pr_body.md
+
+      - name: Check PR description differs from template
+        if: ${{ github.event_name == 'pull_request' }}
+        run: >
+          python .github/scripts/check-pr-description.py
+          --template-file .github/pull_request_template.md
+          --pr-body-file pr_body.md