Enforce revert commit format

## Expected Behavior

Commitlint configuration extending `@commitlint/config-conventional` should enforce recommended revert commit format documented [here](https://github.com/conventional-changelog/conventional-changelog/tree/master/packages/conventional-changelog-angular#revert). A commit of:
```
revert: not following documentation

This commit reverts 12345
```
should fail commit linting.

## Current Behavior

A revert commit not following the default revert regex pattern `/^revert:\s([\s\S]*?)\s*This reverts commit (\w*)\./` will pass commit linting.