utils.el: fix "no lexical binding" warning

Upstream Emacs has enabled warnings for `.el` files with no
lexical-binding directive, so this file triggers a:

    In toplevel form:
    lsp.el:1:1: Warning: file has no ‘lexical-binding’ directive on its first line

Fix that.

utils.el

@@ -1,3 +1,4 @@
+;;; -*- lexical-binding: t; -*-
 (defun py2el (beg end)
   "Helper function for converting Meson data structures from
 Python sources to something more similar to elisp."