Bug#1088064: gtkam: Stop building gimp plugin

[Petter Reinholdtsen <pere@hungry.com>]

[Jeremy Bícha]
> To fix both these issues, please stop building gtkam-gimp. I
> am submitting a merge request to fix this issue:
> https://salsa.debian.org/debian/gtkam/-/merge_requests/1

As the package is orphaned, any Debian developer can implement the
change.  I suspect the gimp team is the best group to decide.  I have no
idea which purpose the plugin have and if it is no longer needed.

My involvement in this package was to give it a git repo on salsa.  I do
not have any imediate plans to do much more with it. :)

-- 
Happy hacking
Petter Reinholdtsen