Fix packaging version for minimal install

Summary:
As explained in pypa/packaging#631, `packaging v22` completely removes `version.LegacyVersion`. This change breaks `compat.py`.

Unfortunately we cannot check for the version of `packaging` inside of `compat.py`, because `version.parse()` used to return a `version.LegacyVersion` in certain instances, but will now throw an error.

Until a more robust fix is developed, we will have to lock the version of `packaging<22` to avoid build errors.

Reviewed By: peiyizhang

Differential Revision: D42275881

fbshipit-source-id: 9eae10b9400efd24b02b2142d219b8a22d16d99e

requirements.txt

@@ -4,6 +4,7 @@ importlib_metadata; python_version < '3.8'
 matplotlib>=2.0.0
 numpy>=1.21,<1.22
 pandas>=1.0.4,<=1.3.5
+packaging<22
 python-dateutil>=2.8.0
 scikit-learn>=0.24.2
 scipy<1.8.0