Upstream CI tests failing because of incompatability between pre-commit>=3.6 and Python 3.8

[jonded94]

Since this commit (84a5fc4) the CI tests are failing.

This is because pre-commit dropped support for Python 3.8 in pre-commit version 3.6.0.

Why is pre-commit always being updated by dependabot? Since this dependency is a dev/lint dependency only, it does not make sense to me dropping support for Python 3.8 of utidylib but instead lock pre-commit to 3.5.0 for example.

[nijel]

I didn't notice the test breakage in #99 and merged that change.

Fixed via #108