chore: release 2.0.0 (#469)

* updated CHANGELOG.md [ci skip]

* updated package.json [ci skip]

* updated samples/package.json

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

Author: release-please[bot]

error-reporting/package.json

@@ -15,7 +15,7 @@
     "test": "mocha --timeout=600000"
   },
   "dependencies": {
-    "@google-cloud/error-reporting": "^1.1.3",
+    "@google-cloud/error-reporting": "^2.0.0",
     "express": "^4.16.3"
   },
   "devDependencies": {