libclc: update website url

old link is dead

GitOrigin-RevId: a3418631e8aa0941b8b57ec2fc3b8d0c7db493be
diff --git a/README.TXT b/README.TXT
index 00ae6bf..57b5242 100644
--- a/README.TXT
+++ b/README.TXT
@@ -49,4 +49,4 @@
 Website
 -------
 
-http://www.pcc.me.uk/~peter/libclc/
+https://libclc.llvm.org/