Bump `click` to 8.0.x

Summary

Upgrade the locked version of click from 7.1.2 to 8.0.x.

Proposed benefits

Catch up on some upstream bug fixes and improvements documented in the changelog, like

• better Windows support
• --help details for flags

and others.

Proposal details

Should be as easy as running poetry update click and validating the CLI works as expected.

Best reasons not to build

• Potential breaking changes in the click API, though none jump from the changelog and our use barely scratches the surface of the API.