use skip_prefix to avoid repeating strings

diff --git a/RelNotes b/RelNotes
index 53d76d1a47e0750b0d8b14287ff3d923ca55b438..bf760914010786c830233effc8b96ddacfb114fd 120000 (symlink)
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes/1.7.12.1.txt
\ No newline at end of file
+Documentation/RelNotes/2.1.0.txt
\ No newline at end of file