This is effectively identical to 2023a, because of the chaos around
Lebanon's short notice DST change.

Bump version to 2022g

Fix broken test configuration

Mypy has gotten more strict about implicit optional, and there were a
few other typing issues that turned up. I've also gone ahead and moved
away from the deprecated `typing.` sequences to `collections.abc`, and
removed uses of `List` and such when I found them.

These are no longer supported on ubuntu-latest, but they work on 20.04.

Upgrade versions in github actions

I no longer really believe GPG signatures are a very useful signal here,
and they are a bit of a pain to continue maintaining, so I'm dropping
the tag signing.

See commit 5053a73 (2021.2) for more
details — this is the second version fo 2021b that we are releasing due
to some controversy upstream in the direction that tzdb should take.

This is really 2021a+ — there is a great deal of controversy upstream
about the inclusion of a number of patches that merge pre-existing zones
into zones with which they differ before 1970.

These changes may be disruptive to test suites and a large number of
people asked the maintainer to make a release containing only the
changes to Samoa and Jordan's DST (which are time-sensitive) and to
continue the debate about the other changes without the added time
pressure. The maintainer cut a release with fewer of the proposed
changes, but still many changes. As a result, there has been some split
in the ecosystem about which binaries to actually deploy — some people
are packaging 2021a + Samoa & Jordan while others are packaging 2021b
as-is.

We will attempt a compromise by releasing 2021a + cherry-picked changes
as 2021.2 and 2021b as 2021.2.post0.

This is useful for the case we find ourselves in now — where we want to
build from a local copy of the tarball built from a repo with
cherry-picked changes.

Starting in version 0.5.0, the default behavior of `pypa/build` is to
first build the sdist, then to buil a wheel from the sdist, see:

    https://pypa-build.readthedocs.io/en/latest/changelog.html#id10

If you specify `-s -w`, both will be built from the local directory.
Since the sdist is the correct release artifact from which to build
wheels, the default behavior is preferred.