Bump psutil from 5.6.5 to 5.6.6

Bumps [psutil](https://github.com/giampaolo/psutil) from 5.6.5 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-5.6.5...release-5.6.6)

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

requirements.txt

@@ -66,7 +66,7 @@ pickleshare==0.7.5
 Pillow==6.2.1
 prometheus-client==0.7.1
 prompt-toolkit==3.0.3
-psutil==5.6.5
+psutil==5.6.6
 pyasn1==0.4.5
 pycparser==2.19
 Pygments==2.5.2