patch 8.2.0406: FileReadCmd event not well tested

Problem:    FileReadCmd event not well tested.
Solution:   Add a test.
diff --git a/src/version.c b/src/version.c
index ed2f86d..f90a427 100644
--- a/src/version.c
+++ b/src/version.c
@@ -739,6 +739,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    406,
+/**/
     405,
 /**/
     404,