XAPI website link updated in README (#6448)

XAPI website deadlink updated.
Closes #6447

Author: last-genius

README.markdown

@@ -11,7 +11,7 @@ Xen API is written mostly in [OCaml](http://caml.inria.fr/ocaml/)
 4.07.
 
 Xapi is the main component produced by the Linux Foundation's
-[Xapi Project](http://xenproject.org/developers/teams/xapi.html).
+[Xapi Project](https://xenproject.org/projects/xapi/).
 
 Build and Install
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