Bump mysqlclient from 1.4.2.post1 to 1.4.4 in /requirements

Bumps [mysqlclient](https://github.com/PyMySQL/mysqlclient-python) from 1.4.2.post1 to 1.4.4.
- [Release notes](https://github.com/PyMySQL/mysqlclient-python/releases)
- [Changelog](https://github.com/PyMySQL/mysqlclient-python/blob/master/HISTORY.rst)
- [Commits](https://github.com/PyMySQL/mysqlclient-python/compare/v1.4.2.post1...v1.4.4)

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

requirements/common.txt

@@ -74,8 +74,8 @@ newrelic==4.20.1.121 \
     --hash=sha256:708ac6a75c76a59e3d6c0d714e2fbb1e4ec7d540f7d34bddd81e61bdb636e895
 
 # Required by Django
-mysqlclient==1.4.2.post1 \
-    --hash=sha256:f257d250f2675d0ef99bd318906f3cfc05cef4a2f385ea695ff32a3f04b9f9a7
+mysqlclient==1.4.4 \
+    --hash=sha256:9c737cc55a5dc8dd3583a942d5a9b21be58d16f00f5fefca4e575e7d9682e98c
 
 # Required by celery
 billiard==3.6.0.0 --hash=sha256:756bf323f250db8bf88462cd042c992ba60d8f5e07fc5636c24ba7d6f4261d84