Update version number to v12.15.0

Command executed by: Arndress#7172

version-info.xml

 <version-info>
-    <current version="12.14.2" />
+    <current version="12.15.0" />
     <changelog>
+        <version number="12.15.0" timestamp="1561576739825">Updates to Akko, Leggy, Roxie, Sola, Revy, Sayori, Lucina, Estelle, Pit, and Nug-chan. Adds Caulifla to testing.</version>
         <version number="12.14.2" timestamp="1561369713328">Dialogue updates to Mae and Mavis.</version>
         <version number="12.14.1" timestamp="1561318125331">L'Arachel has joined the game!</version>
         <version number="12.14.0" timestamp="1561305262538">Moves HK416 and Dark Magician Girl to the incomplete roster.</version>