Bump pip-tools from 5.2.0 to 5.2.1

Bumps [pip-tools](https://github.com/jazzband/pip-tools) from 5.2.0 to 5.2.1.
- [Release notes](https://github.com/jazzband/pip-tools/releases)
- [Changelog](https://github.com/jazzband/pip-tools/blob/master/CHANGELOG.md)
- [Commits](jazzband/pip-tools@5.2.0...5.2.1)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

requirements/dev.txt

@@ -26,7 +26,7 @@ more-itertools==8.3.0     # via pytest
 nodeenv==1.3.5            # via pre-commit
 packaging==20.4           # via -r requirements/docs.in, pallets-sphinx-themes, pytest, sphinx, tox
 pallets-sphinx-themes==1.2.3  # via -r requirements/docs.in
-pip-tools==5.2.0          # via -r requirements/dev.in
+pip-tools==5.2.1          # via -r requirements/dev.in
 pluggy==0.13.1            # via pytest, tox
 pre-commit==2.5.0         # via -r requirements/dev.in
 py==1.8.1                 # via pytest, tox