Update version number to v12.31.0

Command executed by: Arndress#7172

version-info.xml

 <version-info>
-    <current version="12.30.3" />
+    <current version="12.31.0" />
     <changelog>
+        <version number="12.31.0" timestamp="1564852701165">2019 Summer Event! New summer skins for Monika, Ryuji, Juri, Sheena, Sayaka, Nugi-chan, and L'Arachel. New Tiki Bar Background. Also includes updates to Cammy, Chun-Li, R. Mika, Leafy, Misty (HGSS), Erufuda, Emi, and Caulifla.</version>
         <version number="12.30.3" timestamp="1564796643044">Updates to Pit.</version>
         <version number="12.30.2" timestamp="1564721466977">Updates to Leafy and Meia.</version>
         <version number="12.30.1" timestamp="1564687781269">Moves Zone-tan to the Testing Tables after a major update</version>