feat: text support

[joebobmiles]

Creating this since I'm almost done with implementing support for conflict-free text via Yjs YText. Only have a few things left:

• [x] State mapping needs to map between strings and YText objects.
  • [x] Write tests to confirm mapping is correct.
  • [x] Implement string ⇒ YText mapping.
  • [x] Implement YText ⇒ string mapping.
• [ ] Write integration tests
  • How to check that we are actually using YText and not strings?
    • The best way to confirm that we are using YText is to induce a race condition (two users typing at the same time) and look for behavior that indicates we are using strings. YText conflict resolution is non-deterministic, so we can't perform a check for that. But I think string replacement is deterministic, so we should be able to check that.

Will be using this to post updates instead of #39.

[joebobmiles]

:tada: This PR is included in version 1.3.0-rc.1 :tada:

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot :package::rocket:

[joebobmiles]

:tada: This PR is included in version 1.3.0 :tada:

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot :package::rocket: