[fix] readme to include glm::pi from scalar_constants.hpp and not constants.hpp, which seems to be where pi lives as of latest release.

readme.md

@@ -29,7 +29,7 @@ Thanks for contributing to the project by [submitting issues](https://github.com
 #include <glm/mat4x4.hpp> // glm::mat4
 #include <glm/ext/matrix_transform.hpp> // glm::translate, glm::rotate, glm::scale
 #include <glm/ext/matrix_clip_space.hpp> // glm::perspective
-#include <glm/ext/constants.hpp> // glm::pi
+#include <glm/ext/scalar_constants.hpp> // glm::pi
 
 glm::mat4 camera(float Translate, glm::vec2 const& Rotate)
 {