Update raymath.h (#1118)

* Update raymath.h

Added Vector2Rotate Function.

* Update raymath.h

src/raymath.h

@@ -268,6 +268,14 @@ RMDEF Vector2 Vector2Lerp(Vector2 v1, Vector2 v2, float amount)
     return result;
 }
 
+// Rotate Vector by float in Degrees.
+RMDEF Vector2 Vector2Rotate(Vector2 v, float degs)
+{
+    float rads = degs*DEG2RAD;
+    Vector2 result = {v.x * cosf(rads) - v.y * sinf(rads) , v.x * sinf(rads) + v.y * cosf(rads) };
+    return result;
+}
+
 //----------------------------------------------------------------------------------
 // Module Functions Definition - Vector3 math
 //----------------------------------------------------------------------------------