Fix version in header to match CMakeLists.txt
https://github.com/openscenegraph/VirtualPlanetBuilder/issues/5
--- include/vpb/Version.orig	2015-07-01 12:05:16.000000000 -0500
+++ include/vpb/Version	2023-08-09 07:06:39.000000000 -0500
@@ -20,8 +20,8 @@
 
 #define VPB_VERSION_MAJOR       0
 #define VPB_VERSION_MINOR       9
-#define VPB_VERSION_PATCH       11
-#define VPB_VERSION_SOVERSION   11
+#define VPB_VERSION_PATCH       13
+#define VPB_VERSION_SOVERSION   13
 
 /**
  * vpbGetVersion() returns the library version number.