build: fix #332 (#342)

Suggested solution is obtained from https://github.com/CocoaPods/CocoaPods/issues/10104#issuecomment-704862852

ios/fluttertoast.podspec

@@ -16,6 +16,8 @@ Toast Library for FLutter
   s.public_header_files = 'Classes/**/*.h'
   s.dependency 'Flutter'
   s.dependency 'Toast'
+  s.pod_target_xcconfig = { 'EXCLUDED_ARCHS[sdk=iphonesimulator*]' => 'arm64'}
+  s.user_target_xcconfig = { 'EXCLUDED_ARCHS[sdk=iphonesimulator*]' => 'arm64'}
   s.ios.deployment_target = '8.0'
 end