Bump pillow from 8.1.1 to 8.3.2 in /src

Bumps [pillow](https://github.com/python-pillow/Pillow) from 8.1.1 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/8.1.1...8.3.2)

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

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

src/requirements.txt

@@ -6,7 +6,7 @@ pywin32==227; platform_system == "Windows"
 PyObjC; platform_system == "darwin"
 uflash==1.3.0
 adafruit-circuitpython-fancyled==1.3.3
-Pillow==8.1.1
+Pillow==8.3.2
 adafruit-circuitpython-bitmap_font==1.1.0
 adafruit-circuitpython-display-shapes==1.2.0
 adafruit-circuitpython-neopixel==5.0.0