[3.10] GH-97001: Release GIL in termios extension (GH-99503) (#99680)

Without releasing the GIL calls to termios APIs might block the entire interpreter..
(cherry picked from commit 959ba45d75953caa911e16b4c2a277978fc4b9b0)

Co-authored-by: Ronald Oussoren <ronaldoussoren@mac.com>
2 files changed