feat(ci): add shared workflow for "next release" label

.github/workflows/release-checks.yml

@@ -0,0 +1,42 @@
+name: Release Checks
+on:
+    workflow_call:
+        inputs:
+            next-release-label-check:
+                type: boolean
+                default: false
+    pull_request:
+
+permissions:
+    contents: read
+
+jobs:
+    next-release-label-check:
+        name: Check for "next release" label
+        runs-on: ubuntu-latest
+        if: inputs.next-release-label-check
+        steps:
+        -
+            name: Check for "next release" label
+            uses: actions/github-script@v6
+            with:
+                script: |
+                    const { data: pulls } = await github.rest.pulls.list({
+                        owner: context.repo.owner,
+                        repo: context.repo.repo,
+                        state: 'open',
+                    });
+
+                    // check for open PRs which contain the 'next release' label
+                    const openPRs = pulls.filter(pr =>
+                        pr.labels.some(label => label.name === 'next release')
+                    ).map(pr => `  - #${pr.number}: ${pr.title}`);
+
+                    if (openPRs.length > 0) {
+                        const errorMessage = 'Found "next release" label on the following open pull requests:\n'
+                        + openPRs.join('\n')
+                        + '\nPlease merge them before release.';
+                        core.setFailed(errorMessage);
+                    } else {
+                        console.log('No "next release" label found on any open pull requests!');
+                    }

.github/workflows/tests.yml

@@ -48,6 +48,11 @@ jobs:
     static-analysis:
         uses: ./.github/workflows/static-analysis.yml
 
+    release_checks:
+        uses: ./.github/workflows/release-checks.yml
+        with:
+            next-release-label-check: true
+
     build_docs:
       uses: ./.github/workflows/doctum.yml
       with: