Bump psutil from 5.4.6 to 5.4.8

Bumps [psutil](https://github.com/giampaolo/psutil) from 5.4.6 to 5.4.8.
- [Release notes](https://github.com/giampaolo/psutil/releases)
- [Changelog](https://github.com/giampaolo/psutil/blob/master/HISTORY.rst)
- [Commits](giampaolo/psutil@release-5.4.6...release-5.4.8)

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

Author: dependabot-support

requirements.txt

@@ -9,7 +9,7 @@ isodate==0.6.0
 lxml==4.2.5
 microdata==0.6.1
 nltk==3.2.5
-psutil==5.4.6
+psutil==5.4.8
 pyenchant==2.0.0
 pythonwhois==2.4.3
 requests==2.20.1