patch 8.1.0622: adding quickfix items marks items as valid errors

Problem:    Adding quickfix items marks items as valid errors. (Daniel Hahler)
Solution:   Check when items are valid. (Yegappan Lakshmanan, closes #3683,
            closes #3633)
diff --git a/src/version.c b/src/version.c
index 40c3c5a..bb0c81f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -800,6 +800,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    622,
+/**/
     621,
 /**/
     620,