feat(iOS): Bump version to 3.1.3. (#1061)

Author: ChasonTang

DoraemonKit.podspec

@@ -7,7 +7,7 @@
 
 Pod::Spec.new do |s|
   s.name             = 'DoraemonKit'
-  s.version          = '3.1.2'
+  s.version          = '3.1.3'
   s.summary          = 'iOS 各式各样的工具集合'
 
 # This description is used to generate tags and improve search results.