Update dependency probot to v12 [SECURITY]

Author: renovate[bot]

package.json

@@ -12,7 +12,7 @@
     "express": "^4.16.2",
     "just-safe-get": "^1.3.0",
     "node-fetch": "^2.2.0",
-    "probot": "^9.2.15",
+    "probot": "^12.0.0",
     "probot-app-delete-merged-branch": "^1.0.2-0",
     "probot-app-deploy": "^1.1.1-0",
     "probot-app-pr-title": "^1.1.9"