Only renovate the Drone config on a monthly basis

.drone.yml

@@ -57,6 +57,6 @@ steps:
       recursive: true
 ---
 kind: signature
-hmac: c3a0f95e44c6b1fd4e1de228a3c9a55f9edb5e189deb728b681bd7dc55b39565
+hmac: ecdbe7caaffba17813b29689a57849255bc20133c15f51c5d5184068c9c81924
 
 ...

renovate.json

@@ -6,5 +6,11 @@
     ":prHourlyLimitNone",
     ":prConcurrentLimitNone",
     ":separateMultipleMajorReleases"
+  ],
+  "packageRules": [
+    {
+      "matchFileNames": [".drone.yml"],
+      "schedule": ["before 9am on the first day of the month"]
+    }
   ]
 }