Bump mysqlclient from 2.0.3 to 2.2.6

Bumps [mysqlclient](https://github.com/PyMySQL/mysqlclient) from 2.0.3 to 2.2.6.
- [Release notes](https://github.com/PyMySQL/mysqlclient/releases)
- [Changelog](https://github.com/PyMySQL/mysqlclient/blob/main/HISTORY.rst)
- [Commits](PyMySQL/mysqlclient@v2.0.3...v2.2.6)

---
updated-dependencies:
- dependency-name: mysqlclient
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

cross-reference/requirements.txt

@@ -2,7 +2,7 @@ asgiref==3.3.4
 Django==3.2.3
 gunicorn==20.1.0
 mysql-connector==2.2.9
-mysqlclient==2.0.3
+mysqlclient==2.2.6
 pytz==2021.1
 sqlparse==0.4.1
 typing-extensions==3.10.0.0