You don't need to license it, you can just publish it with a declaration that as the author, you are releasing your work in to the public domain. However, in terms of licensing I believe MIT is the most permissive.
Okay, so just take "The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software" out of MIT and call it the Do Whatever You Want Licence. You're not obliged as an author / copyright holder to impose restrictions on people using your work if you don't want to.
Whether Copilot is breaching MIT depends on what constitutes a substantial portion, which I am not qualified to rule on.
