Bump python-dateutil from 2.8.0 to 2.8.1

Bumps [python-dateutil](https://github.com/dateutil/dateutil) from 2.8.0 to 2.8.1.
- [Release notes](https://github.com/dateutil/dateutil/releases)
- [Changelog](https://github.com/dateutil/dateutil/blob/master/NEWS)
- [Commits](dateutil/dateutil@2.8.0...2.8.1)

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

requirements.txt

@@ -103,7 +103,7 @@ xmltodict<0.12.1
 inflection<=0.3.1
 jdcal==1.4.1
 mock<4.0.0
-python-dateutil==2.8.0
+python-dateutil==2.8.1
 pytz==2019.3
 requests==2.22.0
 simplejson==3.16.0