Let's release v1.0.0

[kyrylo]

It's no secret Pry has failed to set realistic constraints for v1.0.0. We have a lot of ambitious issues in our tracker, but there's no traction there. A lot of them are quite complex, so it's no surprise we couldn't achieve what we planned. In order to move things forward I'd like to propose the following:

• start strictly following semantic versioning
  According to SemVer Pry should've been at 1.0.0 when it was released. However, Pry is older than SemVer, so it didn't happen. It's not a big deal, since we can switch to SemVer with 1.0.0.

• define a set of issues for 1.0.0 to be fixed
  Let's start small and humble and include only a few featues with some bug fixes. We can use GitHub's milestones for that. We already have a milestone for 1.0.0: https://github.com/pry/pry/milestone/10. I suggest to revamp it since it doesn't contain the newest features.

• release 1.0.0
  I think the initial plan was to brag about the release 1.0.0 and impress everybody with super cool features. Realistically, we won't be able to brag about it.

Let's ship it 🚀

[brodygov]

@kyrylo Relatedly, is there a plan for a new point release? It's been almost a year since 0.11.3 and there's a lot of stuff on master that would be useful to see out in a version 0.11.4.

Older, stale new release thread: #1448

(I'm encountering #1744 personally.)

[kyrylo]

Yeah, I plan to release v0.12.0 first to ship the stuff that's been sitting there for a while. #1776