Remove deprecated bindings RGB4 RGB1

[dgleich]

This removes the deprecated bindings for RGB4 and RGB1, see discussion:

JuliaIO/ImageMagick.jl#235
and similar fix in ColorTypes.jl
JuliaGraphics/ColorTypes.jl#312

It also requires the new version of ColorTypes in Compat, but that will cause failures until that version is registered.

CC: @ViralBShah, @ararslan

[ViralBShah]

ColorTypes.jl registration PR: JuliaRegistries/General#117694

Let's re-run the CI in an hour or so.

[ViralBShah]

There is an ambiguity test failing:

     Testing Running tests...
Test Failed at /home/runner/work/Colors.jl/Colors.jl/test/runtests.jl:2
  Expression: isempty(detect_ambiguities(Colors))
   Evaluated: isempty(Tuple{Method, Method}[(_convert(::Type{Cout}, ::Type{C1}, ::Type{C1}, c) where {Cout<:Color, C1<:Color} @ ColorTypes ~/.julia/packages/ColorTypes/0RO5O/src/conversions.jl:90, _convert(::Type{Cdest}, ::Type{Odest}, ::Type{Osrc}, g) where {Cdest<:Color, Odest, Osrc<:AbstractGray} @ Colors ~/work/Colors.jl/Colors.jl/src/conversions.jl:75)])

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Project coverage is 96.75%. Comparing base (f0a508b) to head (4664eb9).
Report is 12 commits behind head on master.

Files with missing lines	Patch %	Lines
src/conversions.jl	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #557      +/-   ##
==========================================
- Coverage   98.82%   96.75%   -2.08%     
==========================================
  Files          10        9       -1     
  Lines        1281     1295      +14     
==========================================
- Hits         1266     1253      -13     
- Misses         15       42      +27     

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[ViralBShah]

Commenting out the ambiguity test, everything else runs fine.

[timholy]

Let me take a crack at fixing the ambiguity.

[timholy]

Personally I think we should remove the Invalidations workflow, but we can do that later.

[timholy]

Does this look good to you @ViralBShah? I haven't looked at other PRs. The docbuild failure is unfortunate but is perhaps better fixed separately.

[ViralBShah]

The doc changes are formatting related, and should be straightforward to fix separately. We should fix them before tagging the release.