python-protobuf: update homepage link

Cc: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/python-protobuf/Config.in

@@ -9,4 +9,4 @@ config BR2_PACKAGE_PYTHON_PROTOBUF
 	  Protocol buffers are Google's language-neutral, platform-neutral,
 	  extensible mechanism for serializing structured data.
 
-	  http://code.google.com/p/protobuf/
+	  https://github.com/protobuf-c/protobuf-c