v0.12.1

What's Changed

• Test on different sets of python versions on each os by @smithara in #117
• Update CHAOS-8 reference by @smithara in #118
• Add IGRF-14 reference. Remove deprecated IGRF-12 and CHAOS-6 by @smithara in #119

Full Changelog: v0.12.0...v0.12.1

See https://viresclient.readthedocs.io/en/latest/release_notes.html