Bump elasticsearch from 7.8.1 to 7.9.0

Bumps [elasticsearch](https://github.com/elastic/elasticsearch-py) from 7.8.1 to 7.9.0.
- [Release notes](https://github.com/elastic/elasticsearch-py/releases)
- [Changelog](https://github.com/elastic/elasticsearch-py/blob/master/Changelog.rst)
- [Commits](elastic/elasticsearch-py@7.8.1...7.9.0)

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

requirements-test.txt

@@ -6,5 +6,5 @@ coverage==5.2.1 # pytest-cov
 mock==4.0.2
 port-for==0.4
 mirakuru==2.3.0
-elasticsearch==7.8.1
+elasticsearch==7.9.0
 -e .[tests]