Bump pillow from 6.0.0 to 6.2.0

Bumps [pillow](https://github.com/python-pillow/Pillow) from 6.0.0 to 6.2.0.
- [Release notes](https://github.com/python-pillow/Pillow/releases)
- [Changelog](https://github.com/python-pillow/Pillow/blob/master/CHANGES.rst)
- [Commits](python-pillow/Pillow@6.0.0...6.2.0)

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

Author: dependabot[bot]

venv_requirements.txt

@@ -43,7 +43,7 @@ pandocfilters==1.4.2
 pbr==5.1.3
 pexpect==4.7.0
 pickleshare==0.7.5
-Pillow==6.0.0
+Pillow==6.2.0
 plotly==4.1.0
 prometheus-client==0.6.0
 prompt-toolkit==2.0.9