requirements: update pytest requirement from <6.2.2 to <6.2.3

Updates the requirements on [pytest](https://github.com/pytest-dev/pytest) to permit the latest version.
- [Release notes](https://github.com/pytest-dev/pytest/releases)
- [Changelog](https://github.com/pytest-dev/pytest/blob/master/CHANGELOG.rst)
- [Commits](pytest-dev/pytest@1.0.0b3...6.2.2)

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

dev_requirements.txt

@@ -1,5 +1,5 @@
 jupyter<=1.0.0
-pytest<6.2.2
+pytest<6.2.3
 pytest-benchmark<=3.2.3
 pytest-cov<2.11.2
 pytest-helpers-namespace<=2019.1.8