Bump psutil from 5.6.3 to 5.6.4

Bumps [psutil](https://github.com/giampaolo/psutil) from 5.6.3 to 5.6.4.
- [Release notes](https://github.com/giampaolo/psutil/releases)
- [Changelog](https://github.com/giampaolo/psutil/blob/master/HISTORY.rst)
- [Commits](giampaolo/psutil@release-5.6.3...release-5.6.4)

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

requirements.txt

@@ -110,7 +110,7 @@ simplejson==3.16.0
 timeout-decorator==0.4.1
 
 # required by monitoring
-psutil==5.6.3
+psutil==5.6.4
 django-cors-headers==3.0.2
 django-multi-email-field<=0.5.1
 user-agents