Remove default dependency (#6)

mod.conf

@@ -1,6 +1,5 @@
 name = signs_lib
 author = VanessaE
-depends = default
-optional_depends = intllib, screwdriver, streetspoles, streetlamps, cottages, prefab_redo
+optional_depends = intllib, screwdriver, streetspoles, streetlamps, cottages, prefab_redo, default
 description = Adds signs with readable text.
 min_minetest_version = 5.4.0