patch 8.1.0535: increment/decrement might get interrupted by updating folds

Problem:    Increment/decrement might get interrupted by updating folds.
Solution:   Disable fold updating for a moment. (Christian Brabandt,
            closes #3599)
diff --git a/src/version.c b/src/version.c
index ad633e8..eaaf98a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -793,6 +793,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    535,
+/**/
     534,
 /**/
     533,