make default optional dependency

depends.txt

@@ -1,4 +1,4 @@
-default
 mobs
+default?
 lucky_block?
 intllib?

mod.conf

@@ -1,4 +1,4 @@
 name = mobs_animal
-depends = default, mobs
+depends = mobs
-optional_depends = lucky_block, intllib
+optional_depends = default, lucky_block, intllib
 description = Adds farm animals.