patch 8.1.1530: Travis config is not optimal

Problem:    Travis config is not optimal.
Solution:   Remove system conditions.  Do not use excluding matrix. Cache OSX
            results. (Ozaki Kiichi, closes #4521)
diff --git a/src/version.c b/src/version.c
index 44ce639..510587b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -778,6 +778,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1530,
+/**/
     1529,
 /**/
     1528,