Bump psutil from 5.4.5 to 5.6.6

Bumps [psutil](https://github.com/giampaolo/psutil) from 5.4.5 to 5.6.6.
- [Release notes](https://github.com/giampaolo/psutil/releases)
- [Changelog](https://github.com/giampaolo/psutil/blob/master/HISTORY.rst)
- [Commits](giampaolo/psutil@release-5.4.5...release-5.6.6)

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

requirements.txt

@@ -15,7 +15,7 @@ log-symbols==0.0.11
 MarkupSafe==1.0
 more-itertools==4.1.0
 pluggy==0.6.0
-psutil==5.4.5
+psutil==5.6.6
 py==1.5.3
 pycodestyle==2.4.0
 PyGithub==1.39