Limit Renovate managers (#12)

Limit managers

.github/renovate.json

@@ -8,6 +8,7 @@
   "prBodyTemplate": "{{{table}}}{{{warnings}}}{{{notes}}}{{{changelogs}}}",
   "semanticCommits": "disabled",
   "commitMessageTopic": "{{#if (containsString depName 'teslamate')}}TeslaMate{{else}}{{depName}}{{/if}}",
+  "enabledManagers": ["custom.regex", "github-actions"],
   "customManagers": [
     {
       "customType": "regex",