Update schemas for ASDF standard 1.6.0

[braingram]

No description provided.

[nden]

LGTM

[braingram]

I missed this until now but the $ref here (on main):

asdf-wcs-schemas/resources/schemas/stsci.edu/gwcs/frame-1.0.0.yaml

Line 62 in 4d01f27

$ref: "http://astropy.org/schemas/astropy/coordinates/frames/baseframe-1.0.0"

means that this package should depend on asdf-coordinates-schemas (it already depends on asdf-transform-schemas).

I added asdf-coordinates-schemas as a dependency and I think that slightly changes the plans for release to be:

• merge and release Update schemas for ASDF standard 1.6.0 asdf-transform-schemas#110
• merge and release Update schemas for ASDF standard 1.6.0 asdf-coordinates-schemas#55
• update this PR to add lower pins for the above packages
• merge and release this PR
• update asdf-astropy to be aware of the above changes
• continue... Make asdf standard 1.6.0 stable (default) asdf#1744