Update ICU4X to 2.2

[Manishearth]

Needs a data regen.

[rustbot]

These commits modify the Cargo.lock file. Unintentional changes to Cargo.lock can be introduced when switching branches and rebasing PRs.

If this was unintentional then you should revert the changes before this PR is merged.
Otherwise, you can ignore this comment.

rustc_error_messages was changed

cc @TaKO8Ki

[rustbot]

r? @Mark-Simulacrum

rustbot has assigned @Mark-Simulacrum.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

Why was this reviewer chosen?

The reviewer was selected based on:

• Owners of files modified in this PR: @Mark-Simulacrum

[rustbot]

The list of allowed third-party dependencies may have been modified! You must ensure that any new dependencies have compatible licenses before merging.

cc @davidtwco, @wesleywiser

[Manishearth]

This needed to add a new dep, utf8_iter, to the deps. The dep is maintained by an ICU4X team member (and long term ecosystem participant, hsivonen)