Upgrade: dev deps to latest (#424)

Author: aladdin-add

package.json

@@ -23,22 +23,22 @@
     "eslint-visitor-keys": "^1.1.0"
   },
   "devDependencies": {
-    "browserify": "^7.0.0",
-    "chai": "^1.10.0",
+    "browserify": "^16.5.0",
+    "chai": "^4.2.0",
     "eslint": "^6.0.1",
     "eslint-config-eslint": "^5.0.1",
-    "eslint-plugin-node": "^8.0.0",
+    "eslint-plugin-node": "^9.1.0",
     "eslint-release": "^1.0.0",
     "esprima": "latest",
     "esprima-fb": "^8001.2001.0-dev-harmony-fb",
-    "json-diff": "~0.3.1",
-    "leche": "^1.0.1",
-    "mocha": "^2.0.1",
-    "nyc": "^13.0.1",
-    "regenerate": "~0.5.4",
+    "json-diff": "^0.5.4",
+    "leche": "^2.3.0",
+    "mocha": "^6.2.0",
+    "nyc": "^14.1.1",
+    "regenerate": "^1.4.0",
     "shelljs": "^0.3.0",
     "shelljs-nodecli": "^0.1.1",
-    "unicode-6.3.0": "~0.1.0"
+    "unicode-6.3.0": "^0.7.5"
   },
   "keywords": [
     "ast",