Raise since build to avoid compatibility problems

gradle.properties

@@ -4,7 +4,7 @@ pluginVersion = 0.9.3-alpha.4
 #    Note that an xyz branch corresponds to version 20xy.z and a since build of xyz.*
 #    means that the first possible build is the next branch number after xyz, so e.g.
 #    a since build of 173.* is equal to 181
-pluginSinceBuild = 232
+pluginSinceBuild = 233
 
 # Token for releasing to Jetbrains using the Gradle intellij/publishPlugin task, for more information see the Gradle build file.
 intellijPublishToken=mytoken