libjson-c: Update package URL

Found through UScan.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

package/libs/libjson-c/Makefile

@@ -36,7 +36,7 @@ define Package/libjson-c
   SECTION:=libs
   CATEGORY:=Libraries
   TITLE:=javascript object notation
-  URL:=http://oss.metaparadigm.com/json-c/
+  URL:=https://json-c.github.io/json-c/
 endef
 
 define Package/libjson-c/description