patch 8.0.0239: no CI with an address sanitizer

Problem:    The address sanitizer sometimes finds errors, but it needs to be
            run manually.
Solution:   Add an environment to Travis with clang and the address sanitizer.
            (Christian Brabandt)  Also include changes only on github.
diff --git a/src/version.c b/src/version.c
index d895216..36dbe3a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    239,
+/**/
     238,
 /**/
     237,