patch 8.0.0500: quotestar test is still a bit flaky

Problem:    Quotestar test is still a bit flaky.
Solution:   Add a slower check for v:version.
diff --git a/src/version.c b/src/version.c
index 3b651cc..c3a4779 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    500,
+/**/
     499,
 /**/
     498,