Update intervalbox.jl

[mforets]

Fixes #519

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A few tests could be added here, eg.

x = 0.5 .. 3
a = IntervalBox(A[1]) # 1 .. 2
@test !(x ⊆ a) && a ⊆ x
@test !(x ⊂ a) && a ⊂ x
@test x ∩ a == a ∩ x == A[1]
@test x ∪ a ==  a ∪ x == x

[codecov-commenter]

Codecov Report

Merging #520 (aaad6db) into master (06f49c2) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #520      +/-   ##
==========================================
+ Coverage   90.35%   90.36%   +0.01%     
==========================================
  Files          25       25              
  Lines        1794     1796       +2     
==========================================
+ Hits         1621     1623       +2     
  Misses        173      173              

Impacted Files	Coverage Δ
src/multidim/intervalbox.jl	89.83% <100.00%> (+0.35%)	⬆️

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[lucaferranti]

Could you add those tests and bump the patch version?

In principle, if we accept those we should also support all other operations (arithmetic etc.) but it can be left for future PRs if/when someone needs those.

[lucaferranti]

@lbenet should we cherrypick this to 1.0-dev?