Version check fails, if newest tmux version is installed from source

I am building tmux from source, using zinit. For people using such cutting-edge version of tmux, the version check in tmux-floax fails, because in this case, the tmux version is (at the time of writing) `next-3.6`. See also [this line](https://github.com/tmux/tmux/blob/6ab268c7bb8b6941796ee6f2ad4b628f54a4f28d/configure.ac#L4) in the tmux sources. The fix is quit easy. In the `tmux_version` function in utils.sh append a `| sed 's/next-//'` like this: ```zsh tmux_version() { tmux -V | cut -d ' ' -f 2 | sed 's/next-//' } ``` Should I create a PR?