gui: bump theme version to 4

updates for fastbootd

Change-Id: I02331693ca9a407e0bd30c633f2b799ece7b3636
diff --git a/gui/pages.cpp b/gui/pages.cpp
index cc2f615..a3047bb 100755
--- a/gui/pages.cpp
+++ b/gui/pages.cpp
@@ -61,7 +61,8 @@
 #include "blanktimer.hpp"
 
 // version 2 requires theme to handle power button as action togglebacklight
-#define TW_THEME_VERSION 3
+// version 4 adds fastbootd support
+#define TW_THEME_VERSION 4
 
 #define TW_THEME_VER_ERR -2