mod: adjust to latest release of zig for file writing option

src/root.zig

@@ -25,7 +25,7 @@ fn logFn(
         }, 0o600) catch @panic("Could not append to log file");
         defer std.posix.close(fd);
 
-        var buffer = std.Io.File.Writer.init(.{ .handle = fd }, std.Options.debug_io, &buf);
+        var buffer = fs.File.stderr().writer(&buf);
         var writer = &buffer.interface;
         defer writer.flush() catch unreachable;