Bump packaging from 20.7 to 20.8

Bumps [packaging](https://github.com/pypa/packaging) from 20.7 to 20.8.
- [Release notes](https://github.com/pypa/packaging/releases)
- [Changelog](https://github.com/pypa/packaging/blob/master/CHANGELOG.rst)
- [Commits](https://github.com/pypa/packaging/compare/20.7...20.8)

requirements.txt

@@ -15,7 +15,7 @@ numpy==1.19.4
 outlier==0.2
 utils==1.0.1
 outlier-utils==0.0.3
-packaging==20.7
+packaging==20.8
 pandas==1.1.4
 pluggy==0.13.1
 pyparsing==2.4.7