fix(package): update bootstrap to version 4.4.0

Closes #24

Author: greenkeeper[bot]

package.json

@@ -12,7 +12,7 @@
   "dependencies": {
     "angular": "^1.5.3",
     "backbone": "^1.3.3",
-    "bootstrap": "^3.3.6",
+    "bootstrap": "^4.4.0",
     "ember": "^1.0.0-pre.2",
     "jquery": "^3.1.1",
     "jquery-ui": "^1.10.5",