Lowering volume using the minus sign wth swayosd-client fails with "unexpected argument"

[busybox11]

Since the introduction of Clap in this commit for use with swayosd-client, trying to change the volume with it using a parameter involving the minus sign will fail:

rain@realbox ❯ ./build/src/swayosd-client --output-volume -1
error: unexpected argument '-1' found

Usage: swayosd-client [OPTIONS]

For more information, try '--help'.

Was able to confirm this used to work by checking out to the previous commit. Going to see if I can drop a PR right now.

[busybox11]

..that was also easy enough. barely used clap before, didn't know what to expect before looking into it haha. Dropping a PR right away could've been easier, I guess this issue can still be useful for future reference?

Fixed by #193