Update Mapbox.js to >=2.2.4 for security fix

[reedloden]

https://srcclr.com/security/cross-site-scripting-xss-through/javascript/s-1918
https://nodesecurity.io/advisories/74
mapbox/mapbox.js@1b393c4

[kgeographer]

+1 This issue has killed an app I'm nearing launch on; how dangerous is it to relax bundle-audit for it?

[reedloden]

@kgeographer Depends if you're vulnerable or not. I would read https://nodesecurity.io/advisories/49 and https://nodesecurity.io/advisories/74 to see if you are vulnerable, or if you could at least use the workarounds... better yet, fork this gem, commit this fix, and then call it from your Gemfile.