Bump deployment target due to SocketRocket

Summary:
^

This should fix our FlipperKit publishing:
https://github.com/facebook/flipper/actions/runs/5551630551/jobs/10138141435

Reviewed By: aigoncharov

Differential Revision: D47633000

fbshipit-source-id: fa931bfd560939a7ff72d075dc679afbd038e557

FlipperKit.podspec

@@ -16,7 +16,7 @@ Pod::Spec.new do |spec|
   spec.source = { :git => 'https://github.com/facebook/flipper.git',
                   :tag=> "v"+flipperkit_version }
   spec.module_name = 'FlipperKit'
-  spec.platforms = { :ios => "10.0" }
+  spec.platforms = { :ios => "11.0" }
   spec.default_subspecs = "Core"
 
   # This subspec is necessary since FBDefines.h is imported as <FBDefines/FBDefines.h>