pyModeS v2.12 release

What's Changed

• Fix description by @dforsi in #129
• Add missing import by @dforsi in #131
• Bds62 baro rounding fix by @JWyman482 in #132
• FLARM decoder by @xoolive in #134
• switch to poetry by @xoolive in #135

Full Changelog: v2.11...v2.12