Add GL_MIN GL_MAX blending equations (#2945)

src/rlgl.h

@@ -298,6 +298,8 @@
 
 // GL blending functions/equations
 #define RL_FUNC_ADD                             0x8006      // GL_FUNC_ADD
+#define RL_MIN                                  0x8007      // GL_MIN
+#define RL_MAX                                  0x8008      // GL_MAX
 #define RL_FUNC_SUBTRACT                        0x800A      // GL_FUNC_SUBTRACT
 #define RL_FUNC_REVERSE_SUBTRACT                0x800B      // GL_FUNC_REVERSE_SUBTRACT
 #define RL_BLEND_EQUATION                       0x8009      // GL_BLEND_EQUATION