Add reusable lint workflow

[benjeffery]

No description provided.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.85%. Comparing base (37cda03) to head (c9b755b).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #396   +/-   ##
=======================================
  Coverage   96.85%   96.85%           
=======================================
  Files           8        8           
  Lines         794      794           
  Branches      150      150           
=======================================
  Hits          769      769           
  Misses         15       15           
  Partials       10       10           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[benjeffery]

Just realised this repo doesn't have any linting. This is what it would look like to add - there are many issues to fix to make the lint pass. In the other tskit repos I have sometimes found real issues with this so might be worth doing, but I don't have time right now.