[Proposal] DateTime.to_utc/1

[thojan...@gmail.com]

What do you think of adding a convenience function:

`DateTime.to_utc(dt)`

Which would be a shortcut for:

`DateTime.shift_zone!(dt, "Etc/UTC")`

As converting back to UTC might be a common need for some applications, and writing systematically "Etc/UTC" is a bit ugly.

[Zubair]

If the same thing is achievable which is a single line of code, I don't think it would be appropriate. It can be easily achieved by  `DateTime.shift_zone!(dt, "Etc/UTC")` 

[thojan...@gmail.com]

We already have `DateTime.utc_now()` as a shortcut for `DateTime.now("Etc/UTC")`. So it would make sense to add `to_utc/1` as a convenience function as well here.