chore(deps): update dependency gts to v6

Author: renovate-bot

package.json

@@ -76,7 +76,7 @@
     "gaxios": "^6.0.0",
     "glob": "^8.0.0",
     "grpc": "1.24.11",
-    "gts": "^5.0.0",
+    "gts": "^6.0.0",
     "js-green-licenses": "^4.0.0",
     "linkinator": "^2.0.0",
     "mocha": "^9.2.2",