[cocos2dx] Fix Xcode project to be compatible with Xcode 12

Does not fix compilation errors in cocos2dx itself, which we can not fix on our end.

spine-cocos2dx/example/proj.ios_mac/spine-cocos2d-x.xcodeproj/project.pbxproj

@@ -1068,6 +1068,7 @@
 				CODE_SIGN_IDENTITY = "iPhone Developer";
 				COMPRESS_PNG_FILES = NO;
 				ENABLE_BITCODE = NO;
+				"EXCLUDED_ARCHS[sdk=*]" = arm64;
 				GCC_DYNAMIC_NO_PIC = NO;
 				GCC_INLINES_ARE_PRIVATE_EXTERN = NO;
 				GCC_PRECOMPILE_PREFIX_HEADER = YES;
@@ -1080,7 +1081,7 @@
 				GCC_SYMBOLS_PRIVATE_EXTERN = NO;
 				HEADER_SEARCH_PATHS = "$(inherited)";
 				INFOPLIST_FILE = ios/Info.plist;
-				IPHONEOS_DEPLOYMENT_TARGET = 6.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 11.0;
 				LIBRARY_SEARCH_PATHS = "";
 				OTHER_LDFLAGS = (
 					"$(_COCOS_LIB_IOS_BEGIN)",
@@ -1089,7 +1090,7 @@
 				SDKROOT = iphoneos;
 				TARGETED_DEVICE_FAMILY = "1,2";
 				USER_HEADER_SEARCH_PATHS = "$(_COCOS_HEADER_IOS_BEGIN) $(_COCOS_HEADER_IOS_END)";
-				VALID_ARCHS = "arm64 armv7";
+				VALID_ARCHS = "$(ARCHS_STANDARD)";
 			};
 			name = Debug;
 		};
@@ -1110,7 +1111,7 @@
 				GCC_SYMBOLS_PRIVATE_EXTERN = NO;
 				HEADER_SEARCH_PATHS = "$(inherited)";
 				INFOPLIST_FILE = ios/Info.plist;
-				IPHONEOS_DEPLOYMENT_TARGET = 6.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 11.0;
 				LIBRARY_SEARCH_PATHS = "";
 				OTHER_LDFLAGS = (
 					"$(_COCOS_LIB_IOS_BEGIN)",
@@ -1119,7 +1120,7 @@
 				SDKROOT = iphoneos;
 				TARGETED_DEVICE_FAMILY = "1,2";
 				USER_HEADER_SEARCH_PATHS = "$(_COCOS_HEADER_IOS_BEGIN) $(_COCOS_HEADER_IOS_END)";
-				VALID_ARCHS = "arm64 armv7";
+				VALID_ARCHS = "$(ARCHS_STANDARD)";
 			};
 			name = Release;
 		};