Automate iOS release (#445)

Summary:
This PR sets up Circle CI to publish pods when github release is made. This PR also updates the Flipper-Folly pod as it didn't build on 32 bit architecture, because `thread_local` was not supported.

Automated publish of cocoapods through Circle CI.
Pull Request resolved: https://github.com/facebook/flipper/pull/445

Reviewed By: danielbuechele

Differential Revision: D15333975

Pulled By: priteshrnandgaonkar

fbshipit-source-id: 7db68efeeebbe344213917f10f9f3ce4132e8cbc

Flipper.podspec

@@ -12,13 +12,14 @@ Pod::Spec.new do |spec|
   spec.public_header_files = 'xplat/Flipper/*.h','xplat/utils/*.h'
   spec.source_files = 'xplat/Flipper/*.{h,cpp,m,mm}','xplat/Flipper/utils/*.{h,cpp,m,mm}'
   spec.libraries = "stdc++"
-  spec.dependency 'Flipper-Folly', '1.3.0'
+  spec.dependency 'Flipper-Folly', '~> 1.3'
   spec.dependency 'Flipper-RSocket', '0.10.4'
   spec.compiler_flags = '-DFLIPPER_OSS=1 -DFB_SONARKIT_ENABLED=1 -DFOLLY_NO_CONFIG -DFOLLY_MOBILE=1 -DFOLLY_USE_LIBCPP=1 -DFOLLY_HAVE_LIBGFLAGS=0 -DFOLLY_HAVE_LIBJEMALLOC=0 -DFOLLY_HAVE_PREADV=0 -DFOLLY_HAVE_PWRITEV=0 -DFOLLY_HAVE_TFO=0 -DFOLLY_USE_SYMBOLIZER=0 -Wall
     -std=c++14
     -Wno-global-constructors'
   spec.platforms = { :ios => "8.0" }
   spec.pod_target_xcconfig = { "USE_HEADERMAP" => "NO",
+                               "ARCHS" => "${ARCHS_STANDARD_64_BIT}",
                                "CLANG_CXX_LANGUAGE_STANDARD" => "c++14",
                                "HEADER_SEARCH_PATHS" => "\"$(PODS_TARGET_SRCROOT)\" \"$(PODS_ROOT)/boost-for-react-native\" \"$(PODS_ROOT)/Flipper-RSocket\" \"$(PODS_ROOT)/DoubleConversion\"" }
 end