Add a "latest" pointer on the CDN to avoid having to update versions manually

[adepue]

Not sure if this is a good or bad idea, but I was thinking it might be useful to just point to a latest version of raven.js instead of having to manually bump versions each time a new version is released?

If this is already available, just ignore me.

[benvinegar]

So, one reason we've avoided this is because we follow semver, and we've introduced "breaking" API behavior in Raven.js in the past (although very rarely, and typically very conservatively).

It would be nice to allow people to say, /latest/3.x/, /latest/2.x/ or something.

[adepue]

Yeah the latest/major version seems nice. Basically take the bug fixes as them come, but breaking changes we have to opt into.

[kamilogorek]

Duplicate of #911