Revert "Revert "[CMake] Bumps minimum version to 3.20.0.""

This reverts commit 92523a35a827539db8557bbc3ecab7f9ea3f6ade.

Reland to see whether CIs are updated.

GitOrigin-RevId: 1ef4c3c859728008cf707cad8d67f45ae5070ae1
1 file changed