Bump pillow from 8.0.1 to 8.1.2 in /src/visuanalytics

Bumps [pillow](https://github.com/python-pillow/Pillow) from 8.0.1 to 8.1.2.
- [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...8.1.2)

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

src/visuanalytics/requirements.txt

@@ -1,5 +1,5 @@
 # App requirements
-Pillow==8.0.1
+Pillow==8.1.2
 numpy==1.19.4
 requests==2.25.0
 gTTS==2.2.1