Add schedule & concurrency to CI workflow

* The `schedule` allows to have a fresh snapshot every night (`--rerun-tasks` should ensure we build against cache)
* The `concurrency` allows to cancel previously running and scheduled workflows: only the last built SNAPSHOT matters

.github/workflows/ci-snapshot.yml

@@ -2,15 +2,26 @@ name: CI SNAPSHOT
 
 on:
   workflow_dispatch:
+
   push:
     branches:
       - main
+      - '*.x'
+
+  schedule:
+    - cron: '0 5 * * *'
+
+concurrency:
+  group: group-snapshot-for-${{ github.ref }}
+  cancel-in-progress: true
 
 jobs:
   build-snapshot:
     uses: spring-io/spring-github-workflows/.github/workflows/spring-artifactory-gradle-snapshot.yml@v2
+    with:
+      gradleTasks: ${{ github.event_name == 'schedule' && '--rerun-tasks' || '' }}
     secrets:
       GRADLE_ENTERPRISE_CACHE_USER: ${{ secrets.GRADLE_ENTERPRISE_CACHE_USER }}
       GRADLE_ENTERPRISE_CACHE_PASSWORD: ${{ secrets.GRADLE_ENTERPRISE_CACHE_PASSWORD }}
       GRADLE_ENTERPRISE_SECRET_ACCESS_KEY: ${{ secrets.GRADLE_ENTERPRISE_SECRET_ACCESS_KEY }}
-      JF_ARTIFACTORY_SPRING: ${{ secrets.JF_ARTIFACTORY_SPRING }}
+      JF_ARTIFACTORY_SPRING: ${{ secrets.JF_ARTIFACTORY_SPRING }}