chore(deps): update dependency gts to v6

Author: renovate-bot

package.json

@@ -108,7 +108,7 @@
     "dedent": "^1.0.0",
     "execa": "^5.0.0",
     "gapic-tools": "^0.4.0",
-    "gts": "^5.0.0",
+    "gts": "^6.0.0",
     "jsdoc": "^4.0.0",
     "jsdoc-fresh": "^3.0.0",
     "jsdoc-region-tag": "^3.0.0",

system-test/fixtures/sample/package.json

@@ -18,6 +18,6 @@
   "devDependencies": {
     "@types/node": "^20.0.0",
     "typescript": "^4.0.0",
-    "gts": "^3.0.0"
+    "gts": "^6.0.0"
   }
 }