Add a lower bound to Click

[bildzeitung]

Minor packaging update

Description

This adds a lower version bound on Click corresponding to the features that interrogate uses.

Motivation and Context

Context is here: https://github.com/econchick/interrogate/issues/81

tl;dr; I got stung by this gotcha and thought this might be a useful update for others

Have you tested this? If so, how?

• created a virtualenv
• ran: pip install click==6.7
• ran: pip install -e .
• observed that pip uninstalled the old click and upgraded it

Checklist for PR author(s)

• [x] Changes are covered by unit tests (no major decrease in code coverage %).
• [x] All tests pass.
• [x] Docstring coverage is 100% via tox -e docs or interrogate -c pyproject.toml (I mean, we should set a good example :smile:).
• [x] Updates to documentation:
  • [x] Document any relevant additions/changes in README.rst.
  • [x] Manually update both the README.rst and docs/index.rst for any new/changed CLI flags.
  • [x] Any changed/added classes/methods/functions have appropriate versionadded, versionchanged, or deprecated directives. Find the appropriate next version in the project's __init__.py file.

Release note

    NONE

[econchick]

very much appreciated @bildzeitung ! I'll make a new 1.4.1 release soon (prob tomorrow) with this change.