jansson: update project URL

Old website redirects to github.

Signed-off-by: Yanase Yuki <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/21279
Signed-off-by: Robert Marko <[email protected]>

package/libs/jansson/Makefile

@@ -35,7 +35,7 @@ define Package/jansson
   SECTION:=libs
   CATEGORY:=Libraries
   TITLE:=Jansson library
-  URL:=http://www.digip.org/jansson/
+  URL:=https://github.com/akheron/jansson
   ABI_VERSION:=4
 endef