Geoipsets

- Add python 3.12 support. No code changes required.
- Github Actions integration tests are now run automatically once a week to build all `geoipsets` and load them into both `nftables` and `ipset/iptables`.

Python 3.11 support has now been tested. No code changes required.

- 50% performance improvement when building `dbip` sets only for `nftables`. See issue 25 and PR 27 .
- Fix an edge case where a new run of `geoipsets` uses a different configuration. Existing sets that will not be re-generated as part of the new run will now be kept instead of deleted.

- Significant performance gains when generating the `MaxMind` datasets. See issue 16 and PR 24 .
- The `dbip` download checksum is now validated. This includes the addtition of `--checksum/--no-checksum` flags. See issue 12 and PR 22 .
- Automatic calculation of `ipset` `maxelem` to avoid issues when a set contains more elements than the `ipset` default. See PR 20. Thanks to johnmave126 .
- Improved security for the example systemd unit file. See issue 18 and PR 21 .

- adds support for Python 3.10
- fixes issue 15

* add command line arguments
* country codes can now be specified on the command line or in an external file, outside of `geoipsets.conf`

Note: If you are upgrading from an earlier version, the default location of the sets has changed. Sets are no longer stored in the current working directory, but in `/tmp` instead. Use the new `--output-dir` option to specify an alternate location.