Added new SublimeLinter protected regions key
Added new SublimeLinter protected regions key

A big update is coming to SublimeLinter, in which wake the default key has been changed.
See:
https://github.com/SublimeLinter/SublimeLinter3/pull/665

The old keys
```
        "sublimelinter-warning-gutter-marks",
        "sublimelinter-error-gutter-marks",
```

May still remain in there for a while after the rollout.
We are going to open another PR at a point in  the future to remove those old keys.
jisaacks/GitGutter