forgejo-ci: add check-backports workflow

.forgejo/workflows/check-backports.yml

@@ -0,0 +1,27 @@
+on:
+  workflow_dispatch:
+
+  schedule:
+    - cron: '0 5 * * *'
+
+jobs:
+  check-backports:
+    name: Check backports repo
+    runs-on: x86_64
+    container:
+      image: alpine:latest
+    env:
+      downstream: https://ayakael.net/api/packages/forge/alpine/v3.21/backports
+      FORGEJO_TOKEN: ${{ secrets.forgejo_token }}
+      LABEL_NUMBER: 4
+    steps:
+      - name: Environment setup
+        run: apk add grep coreutils gawk curl wget bash nodejs git jq sed
+      - name: Get scripts
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 1
+      - name: Check out-of-date packages
+        run: ${{ github.workspace }}/.forgejo/bin/check_ver.sh
+      - name: Create issues
+        run: ${{ github.workspace }}/.forgejo/bin/create_issue.sh