build: Expand lerna version range to accept v6

[JaneJeon]

See #3409.

Even with the peerDependencies: optional, npm will still kick and scream and end your process if you try to use this with lerna v6.

Note that this is NOT a breaking change - and simply allows people with lerna v6 to work with the package. People on lerna v5 will not even notice the difference.

Description

Allows this package to work with lerna v6

Motivation and Context

See above

Usage examples

// commitlint.config.js
module.exports = {};

echo "your commit message here" | commitlint # fails/passes

How Has This Been Tested?

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[escapedcat]

npm will still kick and scream

:D That's what it does. Thanks for the PR! Will do a release.