- Support bleach 5, add packaging and tinycss2 dependencies by
bollwyvl in [1755](https://github.com/jupyter/nbconvert/pull/1755)
- Drop dependency on testpath. by anntzer in
[1723](https://github.com/jupyter/nbconvert/pull/1723)
- Adopt pre-commit by blink1073 in [1744](https://github.com/jupyter/nbconvert/pull/1744), [#1746](https://github.com/jupyter/nbconvert/pull/1746),
[1748](https://github.com/jupyter/nbconvert/pull/1748), [#1749](https://github.com/jupyter/nbconvert/pull/1749), [#1757](https://github.com/jupyter/nbconvert/pull/1757)
- Add pytest settings and handle warnings by blink1073 in
[1745](https://github.com/jupyter/nbconvert/pull/1745)
- Update cli example by leahecole in [1753](https://github.com/jupyter/nbconvert/pull/1753)
- Clean up workflows by blink1073 in [1750](https://github.com/jupyter/nbconvert/pull/1750)