The kr/pty module moved to creack/pty per the kr/pty README[1].
creack/pty brings in support for a number of OS/arch combos that
are lacking in kr/pty.
Run `go mod tidy` while here.
[1] https://github.com/kr/pty/blob/master/README.md
Signed-off-by: Aaron Bieber <aaron@bolddaemon.com>
