fix: upgrade gts from 5.2.0 to 5.3.1

Snyk has created this PR to upgrade gts from 5.2.0 to 5.3.1.

See this package in npm:
gts

See this project in Snyk:
https://app.snyk.io/org/cachiman/project/dddc88ce-48aa-4286-bfb4-7a905c2d0f53?utm_source=github-cloud-app&utm_medium=referral&page=upgrade-pr

packages/google-cloud-policytroubleshooter-iam/package.json

@@ -51,7 +51,7 @@
     "@types/sinon": "^17.0.0",
     "c8": "^9.0.0",
     "gapic-tools": "^0.4.0",
-    "gts": "5.2.0",
+    "gts": "5.3.1",
     "jsdoc": "^4.0.2",
     "jsdoc-fresh": "^3.0.0",
     "jsdoc-region-tag": "^3.0.0",