dependabot: Disable autorebase

Signed-off-by: Álvaro Brey Vilas <alvaro.brey@nextcloud.com>

.github/dependabot.yml

@@ -10,6 +10,7 @@ updates:
             interval: daily
             time: "03:00"
             timezone: Europe/Paris
+        rebase-strategy: "disabled"
         open-pull-requests-limit: 10
         labels:
             - 2. to review