change hardcoded master branch in readme enumeration to HEAD

diff --git a/RelNotes b/RelNotes
index 9f01cfb579bd7f5faed353a39bc96afc91f88b0b..fc657e7d2f4b22ce71b2983bd33d9fca131c0c37 120000 (symlink)
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes/2.11.2.txt
\ No newline at end of file
+Documentation/RelNotes/2.24.0.txt
\ No newline at end of file