r242238 - ReleaseNotes.rst: Bump version to 3.8

[Rafael Espíndola]

> I agree it's slightly harder to commit changes to the branch, but I
> wouldn't call it "really hard". And the alternative of keeping the 3.7
> release notes on trunk, which is now 3.8, is seriously confusing.
> Where should release notes for 3.8 features go in that set-up?
>
> I really think keeping all 3.7 material on the 3.7 branch is the only
> sane approach. I agree committing to the branch might be a little
> harder, but in my nagging emails for release notes (I haven't sent one
> for 3.7 yet), I will provide instructions and offer to land changes
> for anyone who doesn't want to do it themselves. This is also how it
> was done for 3.6.
>
> I know we kept release notes on trunk for some previous releases, but
> I don't think that was a good approach. For example, there was a risk
> that notes didn't get merged into the release (e.g. r214830 were meant
> for 3.5 but didn't get merged).

+1

It is way nicer to have everything 3.7 in the branch.

Thanks,
Rafael