Update versions/3.1.1.md

Co-authored-by: Ralf Handl <[email protected]>

Author: handrews

versions/3.1.1.md

@@ -2936,7 +2936,7 @@ additionalProperties:
   - const: RGB
     title: Red, Green, Blue
     description: Specify colors with the red, green, and blue additive color model
-  - const: cmyk
+  - const: CMYK
     title: Cyan, Magenta, Yellow, Black
     description: Specify colors with the cyan, magenta, yellow, and black subtractive color model
 ```