chore(deps): update dependency gaxios to v4 (#1322)

Co-authored-by: Justin Beckwith <[email protected]>

Author: renovate-bot

package.json

@@ -77,7 +77,7 @@
     "c8": "^7.0.0",
     "cpy": "^8.0.0",
     "express": "^4.15.2",
-    "gaxios": "^3.0.2",
+    "gaxios": "^4.0.0",
     "glob": "^7.0.3",
     "grpc": "1.24.3",
     "gts": "^3.0.0",