Bump pur from 5.4.0 to 5.4.1 (#33)

Bumps [pur](https://github.com/alanhamlett/pip-update-requirements) from 5.4.0 to 5.4.1.
- [Release notes](https://github.com/alanhamlett/pip-update-requirements/releases)
- [Changelog](https://github.com/alanhamlett/pip-update-requirements/blob/master/HISTORY.rst)
- [Commits](alanhamlett/pip-update-requirements@5.4.0...5.4.1)

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements-dev.txt

@@ -8,7 +8,7 @@ docformatter==1.4
 coverage==5.5
 autoflake==1.4
 tox==3.23.1
-pur==5.4.0
+pur==5.4.1
 wheel==0.36.2
 setuptools==56.2.0
 twine==3.4.1