Update release notes

docs/release/release_notes.md

 ## Release 5.3
 There are no database changes in this release but you should update your Stripe webhook API version to 2019-02-19.
 
+* Update required Stripe API version from 2018-11-08 to 2019-02-19.
+* Update stripe-php from 6.19.5 to 6.30.4.
+* Make sure we clear processor specific metadata from payment form when switching payment processor (fixes https://lab.civicrm.org/extensions/stripe/issues/26).
+
 
 ## Release 5.2
 *This release introduces a number of new features, standardises the behaviour of recurring contributions/memberships to match standard CiviCRM functionality and does a major cleanup of the backend code to improve stability and allow for new features.*

info.xml

@@ -12,8 +12,8 @@
     <author>Matthew Wire (MJW Consulting)</author>
     <email>mjw@mjwconsult.co.uk</email>
   </maintainer>
-  <releaseDate>2018-12-14</releaseDate>
-  <version>5.2</version>
+  <releaseDate>2019-03-04</releaseDate>
+  <version>5.3alpha1</version>
   <develStage>stable</develStage>
   <compatibility>
     <ver>5.10.3</ver>