Bump google-closure-library from 20180910.0.0 to 20190301.0.0

Bumps [google-closure-library](https://github.com/google/closure-library) from 20180910.0.0 to 20190301.0.0.
- [Release notes](https://github.com/google/closure-library/releases)
- [Commits](google/closure-library@v20180910...v20190301)

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

package.json

@@ -44,7 +44,7 @@
     "ethereum-address": "^0.0.4",
     "ethereumjs-util": "^6.2.0",
     "ethereumjs-wallet": "^0.6.3",
-    "google-closure-library": "^20180910.0.0",
+    "google-closure-library": "^20190301.0.0",
     "google-protobuf": "^3.6.1",
     "joi": "^10.2.0",
     "lodash": "^4.17.4",