perlmods: update JCMT::Tau to latest version.

This includes the tau relations from the SCUBA-2 calibration
paper.
(cherry picked from commit 9a14fba2e847ce63c606f4e942eec81439bacdca)
perlmods: update JCMT::Tau to latest version.

This includes an update to the SCUBA-2 tau test following
the change to the tau relations.
(cherry picked from commit 1620d9e9bd71d1088727a709d6c9320f0e284f77)