avoid stackoverflow when passing two types that can not be promoted to a matching types in mean_hue

[KristofferC]

The test at

Colors.jl/test/utilities.jl

Line 223 in f143ad9

@test_throws Exception mean_hue(RGB(0.1, 0.2, 0.3), RGB(0.4, 0.5, 0.6))

runs a function that stack overflows. Continuing the process after a stack overflow is not recommended and julia 1.12 prints:

Warning: detected a stack overflow; program state may be corrupted, so further execution might be unreliable.

Instead, catch if we have no match after the promote and throw a normal error.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.75%. Comparing base (4664eb9) to head (68c8bcf).
Report is 12 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #566   +/-   ##
=======================================
  Coverage   96.75%   96.75%           
=======================================
  Files           9        9           
  Lines        1295     1296    +1     
=======================================
+ Hits         1253     1254    +1     
  Misses         42       42           

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