Add GitHub workflow (#149)

.luacheckrc

@@ -0,0 +1,18 @@
+unused_args = false
+allow_defined_top = true
+max_line_length = 999
+
+globals = {
+	"unified_inventory",
+}
+
+read_globals = {
+	string = {fields = {"split", "trim"}},
+	table = {fields = {"copy", "getn"}},
+
+	"minetest", "vector",
+	"ItemStack", "datastorage",
+}
+
+files["callbacks.lua"].ignore = { "player", "draw_lite_mode" }
+files["bags.lua"].ignore = { "player" }