Warn user to uninstall git-duet

[dideler]

Because git-duet also has a git-solo command, so there will be a conflict and whichever script is present last in the PATH will be used.

[dideler]

If you see output like this, it probably means there's a naming conflict with another git-solo script (e.g. git-solo ships with git-duet), and the other script appears in your PATH after git-mob.

↪ git solo -v
0.5.2 ('aed36fb704bf19059e6177e02bff81cb4e6deddd')

[dideler]

If installed via brew, brew uninstall git-duet.

If manually installed via downloaded executable, delete the executables and remove its directory from your PATH if needed.

[dideler]

Resolved in c99027c