Disable imperative issue subjects in gitmagic

[emroussel]

Close #12

[ghost]

Your pull request doesn't follow our guidelines. Please fix the following:

• Pull request description must include verification steps (?)

Click here for details.

Thank you! 🙏

_{This comment was made by GitMagic – Magically enforcing your contribution guidelines.}

[coveralls]

Coverage remained the same at 44.444% when pulling 5dd956e on disable-imperative-issue-subjects-in-gitmagic into 77fc434 on master.

[emroussel]

@AdamVig did you mean to include the rule for commit messages starting with a lower case in GitMagic?

[emroussel]

This was fixed with #32