Update validators requirement from <0.21,>=0.19 to >=0.19,<0.23

Updates the requirements on [validators](https://github.com/python-validators/validators) to permit the latest version.
- [Release notes](https://github.com/python-validators/validators/releases)
- [Changelog](https://github.com/python-validators/validators/blob/master/CHANGES.md)
- [Commits](python-validators/validators@0.19.0...0.22.0)

---
updated-dependencies:
- dependency-name: validators
  dependency-type: direct:production
...

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

requirements/testing.txt

@@ -1,3 +1,3 @@
 pytest-cov>=4,<5
 packaging>=20,<24
-validators>=0.19,<0.21
+validators>=0.19,<0.23