fix(deps): update dependency google-gax to ^0.23.0 (#296)

Author: renovate[bot]

package.json

@@ -49,7 +49,7 @@
     "concat-stream": "^2.0.0",
     "extend": "^3.0.1",
     "google-auth-library": "^2.0.0",
-    "google-gax": "^0.22.0",
+    "google-gax": "^0.23.0",
     "is": "^3.2.1",
     "lodash.merge": "^4.6.1",
     "split-array-stream": "^2.0.0",