Bump psutil from 5.6.3 to 5.6.6

Bumps [psutil](https://github.com/giampaolo/psutil) from 5.6.3 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-5.6.3...release-5.6.6)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements.txt

@@ -3,7 +3,7 @@ matplotlib==3.1.1
 numpy>=1.16.4
 opentracing==2.2.0
 protobuf==3.8.0
-psutil==5.6.3
+psutil==5.6.6
 pytest==5.0.1
 requests==2.22.0
 urllib3==1.25.3