Update LICENSE.md

Add html link

Author: sloriot

LICENSE.md

@@ -2,7 +2,7 @@ License of CGAL files in the Git repository
 ===========================================
 The first vector of diffusion of the CGAL sources is the publication of the
 source tarballs of CGAL releases, twice a year. The file
-`Installation/LICENSE`, in the Git repository, is the file `LICENSE` at the
+[`Installation/LICENSE`](https://github.com/cgal/cgal/blob/master/Installation/LICENSE), in the Git repository, is the file `LICENSE` at the
 root of the source tarballs. It describes the license of all the files of
 the source tarballs.