Bump pytest-xdist from 2.2.0 to 2.2.1

Bumps [pytest-xdist](https://github.com/pytest-dev/pytest-xdist) from 2.2.0 to 2.2.1.
- [Release notes](https://github.com/pytest-dev/pytest-xdist/releases)
- [Changelog](https://github.com/pytest-dev/pytest-xdist/blob/master/CHANGELOG.rst)
- [Commits](pytest-dev/pytest-xdist@v2.2.0...v2.2.1)

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

Author: dependabot-preview[bot]

requirements-test.txt

@@ -4,7 +4,7 @@ setuptools>=21  # minimum installation requirements
 coverage==5.4 # pytest-cov
 pytest==6.2.2
 pytest-cov==2.11.1
-pytest-xdist==2.2.0
+pytest-xdist==2.2.1
 psycopg2-binary==2.8.6; platform_python_implementation != "PyPy"
 psycopg2cffi==2.9.0; platform_python_implementation == "PyPy"
 port-for==0.4