geography/py-proj: Update to 2.6.0

This is a version which requires proj 6, vs a version that cannot work
with proj 6.  It is likely quite different as the old package was old.

Upstream NEWS is missing.

Summary is:

  many minor enhancements and bugfixes

  adapt to changes in proj (if you don't understand proj, this is hard
  to use anyway)

  add Geod class

(gdt)