Bump pillow from 6.1.0 to 6.2.0 in /demo/robotlab

Bumps [pillow](https://github.com/python-pillow/Pillow) from 6.1.0 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@6.1.0...6.2.0)

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

demo/robotlab/requirements-python3.txt

@@ -41,7 +41,7 @@ pandocfilters==1.4.2
 parso==0.5.1
 pexpect==4.7.0
 pickleshare==0.7.5
-pillow==6.1.0
+pillow==6.2.0
 ply==3.11
 prometheus-client==0.7.1
 prompt-toolkit==2.0.9