First: We now pin the icu4x version to an exact number. Minor version
upgrades can result in noisy deprecation warnings and API changes which
cause tests to fail. So let's pin the known-good version exactly.
This patch updates our Rust calendar module to use the new APIs. This
initially caused some test failures due to the new Date::try_new API
(which is the recommended replacement for Date::try_new_from_codes)
having quite a limited year range of +/-9999. So we must use other
APIs (Date::try_from_fields and calendrical_calculations::gregorian)
to avoid these limits.
http://github.com/unicode-org/icu4x/blob/main/CHANGELOG.md#icu4x-22
4b1ecbc9df