add minimum minetest version key for contentdb

2020-06-03 13:00:26 -04:00
--- a/mod.conf
+++ b/mod.conf
@@ -1,3 +1,4 @@
 name = moretrees
 depends = default, biome_lib, vessels
 optional_depends = doors, stairs, moreblocks, intllib, farming
 min_minetest_version = 5.2.0