allow color interpolation in change

[Wikunia]

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• Did I update CHANGELOG.md with whatever changes/features I added with this PR?
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Link to relevant issue(s)
Partially closes #363

How did you address these issues with this PR? What methods did you use?
I've changed the standard interpolation in the change function to use Animations.jl now.
That means we interpolate a single time to get the t value using Animations.jl which is based on the easing function but then also use Animations.jl to interpolate using the t value the actual value that we want to change.

Additionally I saw that JBox only allows strings as colors which shouldn't be the case so I fixed that as well.

[codecov]

Codecov Report

Merging #390 (bcf39b2) into master (0a4f3e0) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head bcf39b2 differs from pull request most recent head 3021b11. Consider uploading reports for the commit 3021b11 to get more accurate results

@@           Coverage Diff           @@
##           master     #390   +/-   ##
=======================================
  Coverage   96.24%   96.25%           
=======================================
  Files          35       35           
  Lines        1519     1521    +2     
=======================================
+ Hits         1462     1464    +2     
  Misses         57       57           

Impacted Files	Coverage Δ
src/shorthands/JBox.jl	100.00% <ø> (ø)
src/action_animations.jl	100.00% <100.00%> (ø)
src/util.jl	97.08% <100.00%> (+0.05%)	⬆️

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[TheCedarPrince]

LGTM - I like the syntax that we now have with this. Feel free to merge.

I wonder if we should add this to a tutorial somewhere. I could see redoing Tutorial 7 with J-Objects and this syntax in mind. But that is another issue. :)

Merge it!

[TheCedarPrince]

Oh actually, can you go ahead and use this PR to bump the release version? That way we can have this released and close another issue or two.