Bump pillow from 8.3.2 to 9.3.0 in /alpaca/alpaca-backtrader

Bumps [pillow](https://github.com/python-pillow/Pillow) from 8.3.2 to 9.3.0.
- [Release notes](https://github.com/python-pillow/Pillow/releases)
- [Changelog](https://github.com/python-pillow/Pillow/blob/main/CHANGES.rst)
- [Commits](python-pillow/Pillow@8.3.2...9.3.0)

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

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

Author: dependabot[bot]

alpaca/alpaca-backtrader/requirements.txt

@@ -14,7 +14,7 @@ matplotlib==3.2.2
 multidict==4.7.6
 numpy==1.19.1
 pandas==1.1.1
-Pillow==8.3.2
+Pillow==9.3.0
 pyparsing==2.4.7
 python-dateutil==2.8.1
 pytz==2020.1