Bump everything to ICU4X 2.1.1 (#7191)

I made a small mistake in the release: most crates got published without
an updated dep on `icu_locale_core` and `icu_provider`. What happened
was that when I updated crate deps I updated the section for ICU4X
crates, but those crates are in a different Cargo.toml "section" and
they didn't get an update (I plan to improve the release checklist to
avoid this problem in the future, it has never been clear about this
step).

These crates don't use ~ deps unlike the rest (see
#4343), which is why they are
separate.

This breaks clients who depend directly on a component crate or
metacrate (say, `icu_calendar`), and they update that: this leads to
combinations like `icu_locale_core 2.0.0` with `writeable 0.6.2`.

ICU4X 2.0 had broken no-alloc support, which meant that it claimed to
support no-alloc but in practice it didn't _work_. But the crates
successfully compiled together. ICU4X 2.1 fixes this. Unfortunately,
ICU4X 2.1 "fixed" no-alloc crates will not work with ICU4X 2.0 "broken"
no-alloc crates.

To prevent people from getting inconsistent lockfiles, we just globally
publish 2.1.1.

A more surgical alternative is to publish 2.1.1 only for component
crates (not for provider/etc crates which people will not depend on
directly anyway).

Author: Manishearth