ci(renovate): Resolve 'invalid regExp for fileMath'

Renovate uses JS Regular Expressions which are not glob. Therefore this
wrong regex has to be sorted out. The solution is inspired by the
fileMath of the flux manager.

renovate.json

@@ -14,7 +14,7 @@
   },
   "regexManagers": [
   {
-      "fileMatch": ["*.yaml$"],
+      "fileMatch": ["\\.yaml$"],
       "matchStrings": [
         "# renovate:\\n\\s+image: \"?'?(?<depName>[^:\\s]+?):(?<currentValue>[^\"]*?)\"?'?\\s"
       ],