Remove webpack-cli from peerDependencies

[calebeby]

Closes #40

Proposed changes

Remove webpack-cli from peerDependencies. It isn't needed as a peer.

Types of changes

• Bugfix (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 not work as expected)

Checklist

• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

[calebeby]

@jsnanigans can you please review this?

[jsnanigans]

@calebeby Thanks for the PR!
I published it in 1.3.1