Bug 1718906 [wpt PR 29561] - Bump pillow from 8.2.0 to 8.3.0 in /tools, a=testonly

Automatic update from web-platform-tests
Bump pillow from 8.2.0 to 8.3.0 in /tools (#29561)

Bumps [pillow](https://github.com/python-pillow/Pillow) from 8.2.0 to 8.3.0.
- [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...8.3.0)

---
updated-dependencies:
- dependency-name: pillow
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

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

wpt-commits: c0aa787ca34ac1c196972e917b9d40efae2061ea
wpt-pr: 29561

testing/web-platform/tests/tools/wptrunner/requirements.txt

@@ -2,7 +2,7 @@ html5lib==1.1
 mozinfo==1.2.2  # https://bugzilla.mozilla.org/show_bug.cgi?id=1621226
 mozlog==7.1.0
 mozdebug==0.3.0
-pillow==8.2.0
+pillow==8.3.0
 urllib3[secure]==1.26.6
 requests==2.25.1
 six==1.16.0