Bump psutil from 5.6.3 to 5.6.6 in /Raspberry-Pi

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] <support@github.com>

Author: dependabot[bot]

Raspberry-Pi/requirements.txt

@@ -1,7 +1,7 @@
 cherrypy==18.1.2
 numpy==1.17.0
 spidev==3.4
-psutil==5.6.3
+psutil==5.6.6
 gpiozero==1.5.1
 RPi.GPIO==0.7.0
 pep3143daemon==0.0.6