Bump pillow from 8.0.1 to 8.1.1 (#531)

Bumps [pillow](https://github.com/python-pillow/Pillow) from 8.0.1 to 8.1.1.
- [Release notes](https://github.com/python-pillow/Pillow/releases)
- [Changelog](https://github.com/python-pillow/Pillow/blob/master/CHANGES.rst)
- [Commits](python-pillow/Pillow@8.0.1...8.1.1)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements-webapp.txt

@@ -28,4 +28,4 @@ typing==3.7.4.3
 tzlocal==2.1
 watchdog==0.10.4
 xtarfile[zstd]==0.0.4
-Pillow==8.0.1
+Pillow==8.1.1

requirements.txt

@@ -1,6 +1,6 @@
 Flask==1.1.2
 Flask-Cors==3.0.9
-Pillow==8.0.1
+Pillow==8.1.1
 apache-libcloud==3.2.0
 applicationinsights==0.11.9
 beautifulsoup4==4.9.3