Put forward a no confidence vote on boris Johnson for his proroguing actions.

What boris Johnson has done is undemocratic and it was done to stop MPs voting on a decision that would affect thousands of people. By shutting down parliament he is not allowing ministers the right to vote or block any decisions.
As a prime minister he has to put decisions to a vote.

We can't accept petitions about appointments, which includes calling for Ministers, including the Prime Minister, to resign or for a vote of no confidence.

We used to accept petitions that called for a vote of no confidence. However, the Petitions Committee can’t schedule votes of no confidence. This was often frustrating and disappointing for petitioners.

If you're concerned about a particular policy or decision that's the responsibility of Government or the House of Commons, you could start a petition about that.
Petitions calling for action on policy are more likely to be an effective way of achieving the change you want.