build: update lerna

Author: dobromir-hristov

Diff for: package.json

@@ -63,7 +63,7 @@
     "karma-sourcemap-loader": "^0.3.7",
     "karma-spec-reporter": "^0.0.31",
     "karma-webpack": "^2.0.3",
-    "lerna": "2",
+    "lerna": "^3.20.2",
     "markdown-it-include": "^1.0.0",
     "mocha": "^5.2.0",
     "mocha-webpack": "^1.0.1",
@@ -117,7 +117,13 @@
     }
   },
   "lint-staged": {
-    "*.{js,json,vue,md}": ["prettier --write", "git add"],
-    "*.{js,vue}": ["eslint --fix", "git add"]
+    "*.{js,json,vue,md}": [
+      "prettier --write",
+      "git add"
+    ],
+    "*.{js,vue}": [
+      "eslint --fix",
+      "git add"
+    ]
   }
 }