GEOS-Chem & HEMCO updates: Merge PRs #2512, #279 (USTAR in DustDead)

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

d132546db Merge PR #2512 (Update dust SFs for DustDEAD w/ USTAR)

and to the GitHub geoschem/HEMCO repository:

2423647 Merge PR #279 (Use USTAR from met in DustDEAD extension)

These PRs now use the friction velocity (USTAR) field from the
meteorology archive in the HEMCO DustDead extension, instead of
trying to compute it from the U10M and V10M winds.  Scale factors
to match totals in Meng et al. [2021] have been updated.

Signed-off-by: Bob Yantosca <yantosca@seas.harvard.edu>