Delete useless folly version in podspec (#382)

Author: taboulot

react-native-image-resizer.podspec

@@ -1,7 +1,6 @@
 require "json"
 
 package = JSON.parse(File.read(File.join(__dir__, "package.json")))
-folly_version = '2021.06.28.00-v2'
 folly_compiler_flags = '-DFOLLY_NO_CONFIG -DFOLLY_MOBILE=1 -DFOLLY_USE_LIBCPP=1 -Wno-comma -Wno-shorten-64-to-32'
 
 Pod::Spec.new do |s|