GEOS-Chem submod update: Merge PR #2224 (Fix units of State_Met%PHIS)

This commit informs the GCClassic superproject about the following
commits that were pushed to the GitHub geoschem/geos-chem repository:

200a56444 Updated changelog for PR #2224
de93e325f Merge PR #2224 (Fix geopotential height units in netCDF file)

This PR fixes incorrect units metadata for State_Met%PHIS.

Signed-off-by: Bob Yantosca <[email protected]>