refactor(config): use new Environ method

src/macos/user.zig

@@ -3,9 +3,8 @@ const std = @import("std");
 /// Returns the current logged-in user's username.
 /// Uses the environment variable `USER`.
 /// The caller is responsible for freeing the allocated memory.
-pub fn getUsername(allocator: std.mem.Allocator) ![]u8 {
-    const username = try std.process.getEnvVarOwned(allocator, "USER");
-    return username;
+pub fn getUsername(allocator: std.mem.Allocator, environ: std.process.Environ) ![]u8 {
+    return try std.process.Environ.getAlloc(environ, allocator, "USER");
 }
 
 pub fn getShell(allocator: std.mem.Allocator) ![]u8 {