Bump the minimum required version for 2.90

This is particular important because 2.90 will coexist with 2.83 LTS, so
we should warn the users of potential loss of data when going from 2.90
to 2.83 and back.

Differential Revision: https://developer.blender.org/D8488

source/blender/blenkernel/BKE_blender_version.h

@@ -44,7 +44,7 @@ extern "C" {
 /* Minimum Blender version that supports reading file written with the current
  * version. Older Blender versions will test this and show a warning if the file
  * was written with too new a version. */
-#define BLENDER_FILE_MIN_VERSION 280
+#define BLENDER_FILE_MIN_VERSION 290
 #define BLENDER_FILE_MIN_SUBVERSION 0
 
 /** User readable version string. */