chore: frees memory allocated for shell info

src/main.zig

@@ -26,6 +26,7 @@ pub fn main() !void {
     const shell = try os_module.getShell(allocator);
     try stdout.print("Shell: {s}", .{shell});
     try bw.flush();
+    allocator.free(shell);
 
     const cpu_info = try os_module.getCpuInfo(allocator);
     try stdout.print("cpu: {s} ({})\n", .{ cpu_info.cpu_name, cpu_info.cpu_cores });