feat(renovate): track yq version in README via custom regex manager

Adds a regex customManager to detect and update the yq version
referenced in README.md, using the mikefarah/yq GitHub releases
datasource.

Co-authored-by: Copilot <copilot@github.com>

renovate.json

@@ -31,6 +31,18 @@
       "depNameTemplate": "actions/checkout",
       "datasourceTemplate": "github-releases",
       "versioningTemplate": "semver"
+    },
+    {
+      "customType": "regex",
+      "fileMatch": [
+        "^README\\.md$"
+      ],
+      "matchStrings": [
+        "`(?<currentValue>[^\\s\"']+)`"
+      ],
+      "depNameTemplate": "mikefarah/yq",
+      "datasourceTemplate": "github-releases",
+      "versioningTemplate": "semver"
     }
   ],
   "packageRules": [