Bump pillow from 8.2.0 to 8.3.1 (#19)

Bumps [pillow](https://github.com/python-pillow/Pillow) from 8.2.0 to 8.3.1.
- [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...8.3.1)

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

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

requirements.txt

@@ -5,7 +5,7 @@ tensorflow==2.6.0
 colorama==0.4.4
 tqdm==4.47.0
 ffmpeg-python==0.2.0
-Pillow==8.2.0
+Pillow==8.3.1
 scikit-image==0.17.2
 h5py==3.1.0
 PyQt5==5.15.4

requirements_3.6.txt

@@ -5,7 +5,7 @@ tensorflow==2.6.0
 colorama==0.4.4
 tqdm==4.47.0
 ffmpeg-python==0.2.0
-Pillow==8.2.0
+Pillow==8.3.1
 scikit-image==0.17.2
 h5py==3.1.0
 PyQt5==5.15.4

requirements_3.9.txt

@@ -5,7 +5,7 @@ tensorflow==2.6.0
 colorama==0.4.4
 tqdm==4.47.0
 ffmpeg-python==0.2.0
-Pillow==8.2.0
+Pillow==8.3.1
 scikit-image==0.18.0
 h5py==3.1.0
 PyQt5==5.15.4