Drop unused browserify

Author: Nicolas Carlo

packages/gitgraph-js/package.json

@@ -53,7 +53,6 @@
   "devDependencies": {
     "@types/node": "^9.4.6",
     "auto-changelog": "1.12.1",
-    "browserify": "^14.5.0",
     "npm-run-all": "^4.1.2",
     "rimraf": "^2.6.2",
     "rollup": "1.10.1",