Bump kubernetes from 18.20.0 to 19.15.0 in /perf-tests (#2128)
Bump kubernetes from 18.20.0 to 19.15.0 in /perf-tests (#2128)

Bumps [kubernetes](https://github.com/kubernetes-client/python) from 18.20.0 to 19.15.0.
- [Release notes](https://github.com/kubernetes-client/python/releases)
- [Changelog](https://github.com/kubernetes-client/python/blob/master/CHANGELOG.md)
- [Commits](https://github.com/kubernetes-client/python/compare/v18.20.0...v19.15.0)

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

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>

Co-authored-by: dependabot[bot] <1c358da00a777d4e9898c1280ab801e2df165188@users.noreply.github.com>
nginxinc/kubernetes-ingress,nginxinc/kubernetes-ingress,nginxinc/kubernetes-ingress,nginxinc/kubernetes-ingress