Bump tower from 0.4.3 to 0.4.4
Bump tower from 0.4.3 to 0.4.4

Bumps [tower](https://github.com/tower-rs/tower) from 0.4.3 to 0.4.4.
- [Release notes](https://github.com/tower-rs/tower/releases)
- [Commits](https://github.com/tower-rs/tower/compare/tower-0.4.3...tower-0.4.4)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
shadowsocks/shadowsocks-rust,shadowsocks/shadowsocks-rust,shadowsocks/shadowsocks-rust,shadowsocks/shadowsocks-rust,zonyitoo/shadowsocks-rust