Update Xojo.gitignore for changes to .obsolete

Updates the *.obsolete ignore to match datestamped .obsolete items from newer IDE versions.

Xojo.gitignore

@@ -8,4 +8,4 @@ Debug*/Debug*.exe
 Debug*/Debug*\ Libs
 *.rbuistate
 *.xojo_uistate
-*.obsolete
+*.obsolete*