shunt: update to 0.1.6

shunt: update to 0.1.6

- *Per-policy `action`, `route` (default) or `bypass` - the equivalent of pbr's `ignore`,
  an exception carved out of every policy below it.
- `keep_local`, default on - a marked packet to one of your own subnets
  stays on `main` instead of taking the policy's default route.
- The ruleset is re-applied when the table is deleted - e.g. with `/etc/init.d/firewall stop`
- README update

Signed-off-by: Dirk Brenken <redacted>
Co-authored-by: Claude <redacted>
Signed-off-by: Dirk Brenken <redacted>