Fix podspec config bug.

Author: yaroslavyaroslav

web3swift.podspec

@@ -16,5 +16,5 @@ Pod::Spec.new do |spec|
     spec.resource_bundle = { "Browser" => "Sources/web3swift/Browser/*.js" }
     spec.frameworks = 'CoreImage'
     spec.dependency 'Starscream', '~> 4.0.4'
-    spec.dependency 'Web3Core', '~> 3.0.0-RC3'
+    spec.dependency 'Web3Core', '~> 3.0.0-RC4'
 end