patch 8.1.0242: Insert mode completion may use an invalid buffer pointer

Problem:    Insert mode completion may use an invalid buffer pointer.
Solution:   Check for ins_buf to be valid. (closes #3290)
diff --git a/src/version.c b/src/version.c
index 6162752..5a263a9 100644
--- a/src/version.c
+++ b/src/version.c
@@ -795,6 +795,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    242,
+/**/
     241,
 /**/
     240,