Bump minor version for next GoogleUtilities release (#1837)

GoogleUtilities.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name             = 'GoogleUtilities'
-  s.version          = '5.2.3'
+  s.version          = '5.3.0'
   s.summary          = 'Google Utilities for iOS (plus community support for macOS and tvOS)'
 
   s.description      = <<-DESC