add zlib urls

packages/z/zlib/xmake.lua

@@ -3,7 +3,8 @@ package("zlib")
     set_homepage("http://www.zlib.net")
     set_description("A Massively Spiffy Yet Delicately Unobtrusive Compression Library")
 
-    add_urls("https://github.com/madler/zlib/archive/$(version).tar.gz")
+    add_urls("https://github.com/madler/zlib/archive/$(version).tar.gz",
+             "https://github.com/madler/zlib.git")
 
     add_versions("v1.2.10", "42cd7b2bdaf1c4570e0877e61f2fdc0bce8019492431d054d3d86925e5058dc5")
     add_versions("v1.2.11", "629380c90a77b964d896ed37163f5c3a34f6e6d897311f1df2a7016355c45eff")