Bump to 1.8.9-SNAPSHOT for future development

Reviewed By: elboman

Differential Revision: D51715050

fbshipit-source-id: 80b94789cf0fec5121642628ff6e850a9f72d26b

Author: Kata Zavor

Diff for: litho-intellij-plugin/src/main/resources/META-INF/plugin.xml

@@ -38,7 +38,7 @@
     </ul>
   ]]>
   </description>
-  <version>1.8.8</version>
+  <version>1.8.9-SNAPSHOT</version>
   <change-notes>
     <![CDATA[
     <h3>1.8.5</h3>