reduce to min/max python versions for test cases, avoid fail-fast, remove pip caching

enable MacOS checks, other python versions

another fix attempt: set the working-directory

another fix attempt: use bash shell to get glob expansion

attempt a fix on windows test cases

enable windows for test cases

implement GitHub Action for testing PMapper on multiple platforms/versions

Merge in v1.1.5 (#105)

hotfix: client_args_map set to None caused errors

v1.1.4 (#99)

v1.1.3 (#87)

v1.1.2 (#85)

v1.1.1 (#79)

v1.1.0 Release (#74)

Bugfix: Allow importing of groups with path != '/' (#51)