Make styling fixes
### BREAKING
- Log level option `log_level` was moved to a distinct `log` config section and renamed to `level` [#768](https://github.com/juanfont/headscale/pull/768)
+
### Changes
- Added support for Tailscale TS2021 protocol [#738](https://github.com/juanfont/headscale/pull/738)
