[VsCoq 2] Release 2.1.0

Hi everyone,

We are pleased to announced v2.1.0 of VsCoq. This release mainly introduces coq 8.19 compatibility among other minor fixes.
Thanks to the Coq Core team for their various adaptations to the new Coq API.
Thanks to LittleJianCH and afdw for their contributions.

Romain for the VsCoq team