Bump up version.

Author: kevin-lyn

STNetTaskQueue.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name         = "STNetTaskQueue"
-  s.version      = "0.0.20"
+  s.version      = "0.0.21"
   s.summary      = "STNetTaskQueue is a networking queue library for iOS and OS X. It's abstract and can be implemented in different protocols."
 
   s.description  = <<-DESC

STNetTaskQueue/Info.plist

@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>0.0.20</string>
+	<string>0.0.21</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>