fix(deps): update dependency redis to v4 (#966)

Author: renovate-bot

packages/google-cloud-vision/samples/package.json

@@ -16,7 +16,7 @@
     "@google-cloud/vision": "^2.4.0",
     "natural": "^5.0.0",
     "pureimage": "^0.3.0",
-    "redis": "^3.0.0",
+    "redis": "^4.0.0",
     "yargs": "^16.0.0"
   },
   "devDependencies": {