Click-option-group

* Add `optgroup.help_option` decorator to add help option to the group (PR [50](https://github.com/click-contrib/click-option-group/pull/50))
* Use GitHub Actions instead of Travis CI for CI
* Delete tox runner
* Add Python 3.11 to the setup classifiers

* Add `tests/` directory to tarball
* Add `tests_cov` extra dependencies for testing with coverage

* Move frame gathering into error code path (PR [34](https://github.com/click-contrib/click-option-group/pull/34))
* Fix typos (PR [37](https://github.com/click-contrib/click-option-group/pull/37))
* PEP 561 support (PR [42](https://github.com/click-contrib/click-option-group/pull/42))
* Update docs dependencies and Travis CI Python version matrix (PR [43](https://github.com/click-contrib/click-option-group/pull/43))

* Update Click dependency version to `<9` (Issue [33](https://github.com/click-contrib/click-option-group/issues/33))

* Do not use default option group name. An empty group name will not be displayed
* Slightly edited error messages
* All arguments except `name` in `optgroup` decorator must be keyword-only

* Fix incompatibility with autocomplete: out of the box Click completion and click-repl (Issue [14](https://github.com/click-contrib/click-option-group/issues/14))