.github/workflows: run xbps-cycles daily.

Should help in catching cyclic dependencies early.

Rename lockthreads.yml to include all scheduled CI tasks.

.github/workflows/cron.yml

@@ -1,4 +1,4 @@
-name: 'Lock threads'
+name: 'Scheduled tasks'
 
 on:
   schedule:
@@ -13,3 +13,8 @@ jobs:
           github-token: ${{ github.token }}
           pr-lock-inactive-days: '90'
           process-only: 'prs'
+  cycles:
+    runs-on: ubuntu-latest
+    steps:
+      - run: apt-get install -y python3-networkx
+      - run: common/scripts/xbps-cycles.py