Bump pillow from 8.2.0 to 8.3.2 in /apiserver

Bumps [pillow](https://github.com/python-pillow/Pillow) from 8.2.0 to 8.3.2.
- [Release notes](https://github.com/python-pillow/Pillow/releases)
- [Changelog](https://github.com/python-pillow/Pillow/blob/master/CHANGES.rst)
- [Commits](https://github.com/python-pillow/Pillow/compare/8.2.0...8.3.2)

---
updated-dependencies:
- dependency-name: pillow
  dependency-type: direct:production
...

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

apiserver/requirements.txt

@@ -21,7 +21,7 @@ Jinja2==2.11.3
 MarkupSafe==1.1.1
 oauthlib==3.1.0
 packaging==20.0
-Pillow==8.2.0
+Pillow==8.3.2
 pycparser==2.19
 Pygments==2.7.4
 pyparsing==2.4.6