Bump tox from 3.18.1 to 3.19.0

Bumps [tox](https://github.com/tox-dev/tox) from 3.18.1 to 3.19.0.
- [Release notes](https://github.com/tox-dev/tox/releases)
- [Changelog](https://github.com/tox-dev/tox/blob/master/docs/changelog.rst)
- [Commits](https://github.com/tox-dev/tox/compare/3.18.1...3.19.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>
diff --git a/requirements/dev.txt b/requirements/dev.txt
index 3be6a79..1959dc5 100644
--- a/requirements/dev.txt
+++ b/requirements/dev.txt
@@ -24,7 +24,7 @@
 pyyaml==5.3.1             # via pre-commit
 six==1.15.0               # via packaging, pip-tools, tox, virtualenv
 toml==0.10.1              # via pre-commit, pytest, tox
-tox==3.18.1               # via -r requirements/dev.in
+tox==3.19.0               # via -r requirements/dev.in
 virtualenv==20.0.21       # via pre-commit, tox
 
 # The following packages are considered to be unsafe in a requirements file: