Feature request: Option to ignore certain accounts

[hrj]

There are some user accounts, such as dependency update bots, which don't sign off their commits. It is a chore to manually set the DCO status to pass.

It would be nice to have a config option to ignore some accounts.

Ideally, the proposed config option (and this app) would use (and validate) the github account of the one raising a PR, but I have no idea if that is possible. This is to prevent ignoring based on commit info, which can be easily doctored.