build(deps): Bump Lerna to v4.0.0

fixes security alert for ssri package

Author: eheikes

package.json

@@ -31,7 +31,7 @@
   "devDependencies": {
     "cross-env": "^5.2.0",
     "jasmine": "^2.9.0",
-    "lerna": "^3.22.1",
+    "lerna": "^4.0.0",
     "nyc": "^14.1.0",
     "proxyquire": "^1.8.0",
     "standard": "^12.0.1"