fix(package): update bootstrap to version 4.1.2

Closes #29

Author: greenkeeper[bot]

package.json

@@ -42,7 +42,7 @@
     "url": "https://github.com/bripkens/admin/issues"
   },
   "dependencies": {
-    "bootstrap": "3",
+    "bootstrap": "^4.1.2",
     "bootswatch": "^3.3.7",
     "express": "^4.15.0",
     "express-prettify": "^0.0.7",