patch 8.2.2431: warning for -fno-strength-reduce with Clang 11

Problem:    Warning for -fno-strength-reduce with Clang 11.
Solution:   Adjust check for clang version number.
diff --git a/src/version.c b/src/version.c
index 56a0797..6854c10 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2431,
+/**/
     2430,
 /**/
     2429,