message: Finalize changelog for v1.37.0
diff: # Change Log
  -## [1.37.0] - Development
  +## [1.37.0] - 2020-03-10
  Updated the MaterialX library to the v1.37 specification. See the [v1.37 changelist](http://www.materialx.org/assets/MaterialX.v1.37REV2.Changelist.pdf) for full details.
  @@ -16,7 +16,7 @@ Updated the MaterialX library to the v1.37 specification. See the [v1.37 change
  - Replaced GeomAttr elements with GeomProp elements.
  - Replaced backdrop nodes with Backdrop elements.
  - Aligned Matrix33 and Matrix44 with the row-vector convention, for improved consistency with Imath, USD, and other libraries.
  -- Updated the stb_image library to version 2.23
  +- Updated the stb_image library to version 2.23.
  ## [1.36.5] - 2020-01-11
  