deps: update zg

dude_the_builder transferred maintainership to Sam Atman. Update
build.zig.zon to match

build.zig.zon

···
             .lazy = true,
         },
         .zg = .{
-            .url = "git+https://codeberg.org/dude_the_builder/zg?ref=master#689ab6b83d08c02724b99d199d650ff731250998",
-            .hash = "12200d1ce5f9733a9437415d85665ad5fbc85a4d27689fd337fecad8014acffe3aa5",
+            .url = "https://codeberg.org/atman/zg/archive/v0.13.2.tar.gz",
+            .hash = "122055beff332830a391e9895c044d33b15ea21063779557024b46169fb1984c6e40",
         },
         .libxev = .{
             .url = "git+https://github.com/mitchellh/libxev#f6a672a78436d8efee1aa847a43a900ad773618b",