Update Podspec

Author: Malcolm Jarvis

MultipartDataBuilder.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |spec|
   spec.name = "MultipartDataBuilder"
-  spec.version = "3.0.0-alpha4"
+  spec.version = "3.0.0-alpha5"
   spec.license = "MIT"
   spec.summary = "Micro framework for creating multipart forms"
   spec.homepage = "https://github.com/mogstad/multipart_data_builder"
@@ -9,7 +9,7 @@ Pod::Spec.new do |spec|
   }
   spec.source = { 
     :git => "https://github.com/mogstad/multipart_data_builder.git", 
-    :tag => "v3.0.0-alpha4"
+    :tag => "v3.0.0-alpha5"
   }
   spec.platforms = {
     :ios => "9.0"