[Ser2net-devel] Gensio 3.0.0 released

[Corey M. <co...@mi...>]

This release is a major release, but the only major thing is all the
deprecated sergensio code has been removed. ser2net, the rust and go
interfaces have all had that removed for a while and hopefully any other
users have removed it. sergensio, in the end, just didn't make any
sense.

There are also some minor bug fixes, some documentation improvements,
some minor improvements, and a bug fix around ax25 where it was
reporting the close of the last channel too soon.