Upgrade tcell-term to v0.2.0
Use Start method from tcell-term. This prevents aerc from needing to
wait until the command has started to continue. The tcell-term start
method blocks until the command is started, similar to cmd.Start. By
doing so, we prevent a race condition between aerc and tcell-term on
access to cmd.Process.
Remove cleanup of cmd, this is all already handled by tcell-term when
Close is called.
Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>
Acked-by: Robin Jarry <robin@jarry.cc>