CI: check if CHANGES file was edited

Author: zbaylin

.github/workflows/main.yaml

@@ -57,3 +57,27 @@ jobs:
         with:
           name: html-docs
           path: _build/default/_doc/_html/
+
+  check-changes:
+    runs-on: ubuntu-latest
+    if: github.event_name == 'pull_request'
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Determine if CHANGES changed
+        id: changes-changed
+        uses: tj-actions/changed-files@v39
+        with:
+          files_yaml: |
+            changes:
+              - 'CHANGES'
+
+      - name: Fail if CHANGES did not change
+        if: steps.changes-changed.outputs.changes_any_changed == 'false'
+        run: |
+          echo "No changes made to the CHANGES file."
+          echo "Please update the file with your changes."
+          exit 1