chore(config): migrate config .github/renovate.json (#604)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: David May <[email protected]>

Author: renovate[bot]

.github/renovate.json

@@ -6,8 +6,8 @@
   "customManagers": [
     {
       "customType": "regex",
-      "fileMatch": [
-        "\\.go$"
+      "managerFilePatterns": [
+        "/\\.go$/"
       ],
       "matchStrings": [
         "Value:\\s+\"(?<depName>[^\"]+):(?<currentValue>[^\"]+)@sha256:[a-f0-9]{64}\""