fix(deps): update dependency @google-cloud/pubsub to ^0.28.0 (#253)

Author: renovate[bot]

packages/google-privacy-dlp/samples/package.json

@@ -16,7 +16,7 @@
   },
   "dependencies": {
     "@google-cloud/dlp": "^0.10.0",
-    "@google-cloud/pubsub": "^0.27.0",
+    "@google-cloud/pubsub": "^0.28.0",
     "mime": "^2.3.1",
     "yargs": "^13.0.0"
   },