Co-authored-by: Jason R. Coombs <jaraco@jaraco.com>

guess_next_simple_semver previously would error on trying to convert the
'rc0' part of a version such as '1.2.0rc1' to an int, even if it was
told to retain only the first two parts. (It would actually only error
on Python 2, where the conversion to int was non-lazy)

Now if it's told to retain only the first two parts, it won't try to
convert anything after the first two dots to an int, so it won't error.
The outcome is the same as if the bit after the second dot was a valid
int (which was going to be ignored anyway, we just now don't error on
it).

This is useful for the release-branch-semver scheme, which wants to be
able to find the next minor version even if the most recent version is a
release candidate.

This is a scheme that assumes that the upcoming release for most
branches is a minor release, and that only for release branches
(those whose branch names parse as a version number according to current
configuration) is the upcoming version a patch release.

Better document the differences between the schemes in README.rst

Allow getting the version from the parent directory suffix.

port testsuite to pathlib, and try to resolve windows short paths

trace git toplevel mismatch (observed on win32 name shortening)

exclude python2 on windows

remove the appveyor config, its broken

drop most travis envs that we have in github workflows now

add actions for creating egg artifacts/wheels/sdists

WIP: experiment with act

WIP: fix workflow typo

WIP: add missed runs-on

fix typoed excludes

fixup: upload actuall wheel/sdist in the build step

style fixes for the actions config

Add a `parentdir_prefix_version` config parameter which allows lets
setuptools_scm get a version string from the name of the parent
directory: if `parentdir_prefix_version = "foo-"` and the parent
directory is named `foo-v12.34`, then the version is 12.34.  This is
only active if the parameter is set (it defaults to unset, i.e. the
feature is opt-in), if getting the version from the SCM failed, *and*
there's no metadata already present.  However, this has higher priority
than `fallback_version` (which remains the last-resort fallback).

This feature is intended to support the tarballs that GitHub
automatically creates for all releases, which have no metadata but
follow the correct naming scheme for the feature to work.

This feature is directly inspired from versioneer's `parentdir_prefix`
setting.

 Change ScmVersion.time to UTC

The default `git describe` command had an undocumented `--match *.*` in it,
intended to skip over tags that may represent human-readable checkpoints.

Unfortunately this means it would be ignoring single-component versions.

Instead look for presence of digits in the tag, it's still a heuristic, but
it should cover all previous cases, and fix single component versions.

This makes sure that even if there's only a single group of digits in the
version, it's correctly extracted, and any suffix ignored.

Also add tests for those particular cases to avoid regressions.

See Issue #411 for debugging details.