Bump google-closure-library from 20160315.0.0 to 20200315.0.0

Bumps [google-closure-library](https://github.com/google/closure-library) from 20160315.0.0 to 20200315.0.0.
- [Release notes](https://github.com/google/closure-library/releases)
- [Commits](google/closure-library@v20160315...v20200315)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

package-lock.json

@@ -18,7 +18,7 @@
   "devDependencies": {
     "chai": "4.3.4",
     "google-closure-compiler": "20160315.2.0",
-    "google-closure-library": "20160315.0.0",
+    "google-closure-library": "20200315.0.0",
     "gulp": "4.0.2",
     "gulp-clean-css": "4.3.0",
     "gulp-closure-compiler": "0.4.0",