Release v0.4.0 (#135)

Author: JustinBeckwith

kms/package.json

@@ -14,7 +14,7 @@
     "test": "mocha system-test"
   },
   "dependencies": {
-    "@google-cloud/kms": "^0.3.0"
+    "@google-cloud/kms": "^0.4.0"
   },
   "devDependencies": {
     "chai": "^4.2.0",