chore: release 2.2.0 (#853)

Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com>
Co-authored-by: Benjamin E. Coe <bencoe@google.com>

Author: release-please[bot]

vision/samples/package.json

@@ -13,7 +13,7 @@
     "test": "mocha system-test --timeout 600000"
   },
   "dependencies": {
-    "@google-cloud/vision": "^2.1.2",
+    "@google-cloud/vision": "^2.2.0",
     "natural": "^2.0.0",
     "pureimage": "^0.2.1",
     "redis": "^3.0.0",