Bug#967519: haskell-diagrams-gtk: depends on deprecated GTK 2

[Simon McVittie]

On Tue, 04 Aug 2020 at 11:48:20 +0100, smcv at debian.org wrote:
> This package has Build-Depends on GTK 2 (libgtk2.0-dev), or produces
> binary packages with a Depends on GTK 2.

It seems nothing in Debian depends or build-depends on
haskell-diagrams-gtk. Is it still useful? If not, can we remove it from
unstable before the Debian 13 release, to discourage the addition of
new software that depends on GTK 2?

Thanks,
    smcv