Bump pytest-xdist from 2.1.0 to 3.5.0 in /tests

Bumps [pytest-xdist](https://github.com/pytest-dev/pytest-xdist) from 2.1.0 to 3.5.0.
- [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@v2.1.0...v3.5.0)

---
updated-dependencies:
- dependency-name: pytest-xdist
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

tests/e2e_tests/requirements.txt

@@ -27,7 +27,7 @@ pytest-cov==2.11.1
 pytest-html
 pytest-json-report==1.5.0
 # pytest-metadata==1.7.0
-pytest-xdist==2.1.0
+pytest-xdist==3.5.0
 pytest-timeout==2.2.0
 
 # for common utils, e2e_tests