Disable Renovate

We don't need the latest libraries any more, since we aren't actively working on Normandy. Github's Dependabot will provide security updates.

renovate.json

@@ -1,13 +0,0 @@
-{
-  "extends": ["config:base"],
-  "docker-compose": {
-    "digest": {
-      "enabled": false
-    }
-  },
-  "dockerfile": {
-    "pinDigests": true
-  },
-  "timezone": "UTC",
-  "schedule": ["before 13:00 on mondays"]
-}