cifs: update internal version number

To 2.31
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/cifsfs.h

@@ -160,5 +160,5 @@ extern struct dentry *cifs_smb3_do_mount(struct file_system_type *fs_type,
 extern const struct export_operations cifs_export_ops;
 #endif /* CONFIG_CIFS_NFSD_EXPORT */
 
-#define CIFS_VERSION   "2.30"
+#define CIFS_VERSION   "2.31"
 #endif				/* _CIFSFS_H */