Enforce to use OSG 3.7.0 or greater on macOS Catalina

[jslee02]

OpenSceneGraph 3.6.5 or less are not compatible with macOS 10.15 (Catalina) or greater (openscenegraph/OpenSceneGraph#926, #1439). This PR increases the required minimum OSG version for macOS Catalina to 3.7.0 that includes the fix.

Resolves #1439

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[codecov]

Codecov Report

Merging #1479 into master will increase coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1479      +/-   ##
==========================================
+ Coverage   58.18%   58.20%   +0.02%     
==========================================
  Files         412      412              
  Lines       29913    29913              
==========================================
+ Hits        17406    17412       +6     
+ Misses      12507    12501       -6     

Impacted Files	Coverage Δ
dart/dynamics/EulerJoint.cpp	73.00% <0.00%> (+3.68%)	⬆️