package/libsndfile: update project home page url

The libsndfile package homepage url [1] points to an old site in which
the last update is for version 1.0.28 (April 2 2017). This site does
not seem to be maintained anymore.

This commit updates the libsndfile homepage url to [2].

[1] http://www.mega-nerd.com/libsndfile/
[2] https://libsndfile.github.io/libsndfile/

Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libsndfile/Config.in

@@ -5,4 +5,4 @@ config BR2_PACKAGE_LIBSNDFILE
 	  containing sampled sound (such as MS Windows WAV and the
 	  Apple/SGI AIFF format) through one standard library interface.
 
-	  http://www.mega-nerd.com/libsndfile/
+	  https://libsndfile.github.io/libsndfile/