use watcher instead of polling

[extrawurst]

use notify to watch git instead of permanent polling

[extrawurst]

unfortunately this introduces massive bloat of dependencies and reintroduces the outdated mio 0.6 with its security problematic outdated net2: notify-rs/notify#248

[0xpr03]

Note: We're not depending on mio 0.6 anymore

[extrawurst]

@0xpr03 yeah but I am waiting for a stable release of 5.0

[extrawurst]

or I am just using https://github.com/facebook/watchman

ok that requires another binary to be installed - what a joke