feat: upgrade gaxios from 5.0.2 to 6.6.0

Snyk has created this PR to upgrade gaxios from 5.0.2 to 6.6.0.

See this package in npm:
gaxios

See this project in Snyk:
https://app.snyk.io/org/cachiman/project/43d11d98-df53-4952-8a8e-45972735a107?utm_source=github&utm_medium=referral&page=upgrade-pr

packages/policy/package.json

@@ -31,7 +31,7 @@
   "dependencies": {
     "@google-cloud/bigquery": "^6.0.2",
     "code-suggester": "^4.1.0",
-    "gaxios": "^5.0.1",
+    "gaxios": "^6.6.0",
     "gcf-utils": "^14.2.0",
     "jsonwebtoken": "^9.0.0",
     "lru-cache": "^7.14.0",