Examples: Apple+OpenGL2: silence warnings.

Example is precisely to demonstrate OpenGL.

examples/example_apple_opengl2/main.mm

@@ -6,6 +6,7 @@
 // - Documentation        https://dearimgui.com/docs (same as your local docs/ folder).
 // - Introduction, links and more at the top of imgui.cpp
 
+#define GL_SILENCE_DEPRECATION
 #import <Cocoa/Cocoa.h>
 #import <OpenGL/gl.h>
 #import <OpenGL/glu.h>
@@ -32,7 +33,7 @@
 
 #ifndef DEBUG
     GLint swapInterval = 1;
-    [[self openGLContext] setValues:&swapInterval forParameter:NSOpenGLCPSwapInterval];
+    [[self openGLContext] setValues:&swapInterval forParameter:NSOpenGLContextParameterSwapInterval];
     if (swapInterval == 0)
         NSLog(@"Error: Cannot set swap interval.");
 #endif