Relaxed GLURaw dependency.

Author: svenpanne

OpenGL.cabal

@@ -154,7 +154,7 @@ library
     ObjectName   >= 1.1 && < 1.2,
     StateVar     >= 1.1 && < 1.2,
     OpenGLRaw    >= 2.1 && < 2.5,
-    GLURaw       >= 1.3 && < 1.5
+    GLURaw       >= 1.3 && < 1.6
   default-language: Haskell2010
   other-extensions:
     CPP