Renovate: sign off commits

Signed-off-by: tobiasKaminsky <tobias@kaminsky.me>

renovate.json5

@@ -2,7 +2,8 @@
   "$schema": "https://docs.renovatebot.com/renovate-schema.json",
   "extends": [
       "config:recommended",
-      ":switchToGradleLite"
+      ":switchToGradleLite",
+      ":gitSignOff"
   ],
   "timezone": "Europe/Berlin",
   "labels": [