Georss-ign-sismologia-client

* Fix list of supported Python versions.

* Bumped version of upstream [python-georss-client](https://github.com/exxamalte/python-georss-client) library to v0.17 that fixes a backwards compatibility issue with a fault in v0.16.
* Added Python 3.11 support.
* Added Python 3.12 support.
* Removed Python 3.7 support.
* Bumped library versions: black, flake8, isort.
* Migrated to pytest.
* Code quality improvements.

* Fixed publication date where day and month were accidentally swapped in certain cases (thanks joaopedrotaveira).
* Added more test cases.

* No functional changes.
* Added Python 3.10 support.
* Removed Python 3.6 support.
* Using version 0.15 of upstream [python-georss-client](https://github.com/exxamalte/python-georss-client) library.
* Bumped library versions: black, flake8, isort.
* Code clean-up.

* Excluded tests from package (thanks onkelbeh).

* Added Python 3.8 support.
* Added Python 3.9 support.
* Added license tag.
* Bump georss_client to v0.14.
* Migrated to github actions.
* General code improvements.