chore(deps): update dependency gts to v2.0.0 (#343)

Author: renovate-bot

packages/google-cloud-bigquery-datatransfer/package.json

@@ -53,7 +53,7 @@
     "eslint-config-prettier": "^6.0.0",
     "eslint-plugin-node": "^11.0.0",
     "eslint-plugin-prettier": "^3.1.0",
-    "gts": "2.0.0-alpha.9",
+    "gts": "2.0.0",
     "jsdoc": "^3.6.2",
     "jsdoc-fresh": "^1.0.1",
     "jsdoc-region-tag": "^1.0.2",