build: update dependency lerna to v3.8.0

Author: renovate-bot

package.json

@@ -24,7 +24,7 @@
     "gulp-sourcemaps": "2.6.4",
     "gulp-typescript": "5.0.0",
     "jest": "23.6.0",
-    "lerna": "3.7.1",
+    "lerna": "3.8.0",
     "merge2": "1.2.3",
     "prettier": "1.15.3",
     "react": "16.5.2",