While getting rid of Park Geun-Hye certainly made this easier - I think this has more to do with Kim Jong Un and also the warm reception N. Korea got at the recent winter Olympics in South Korea.
That said I would be cautious how far this would go. I suspect a lot of N. Koreas militaristic acts and statements over the years is not because of any actual desire but war, but just posturing to help in negotiations over tariffs and aid.
I am also going to take the unpopular opinion and say that Trump does deserve some credit. Under many past Presidents, the N. Korean government knew America would never use military force and acted accordingly. Under Trump, they have good reason to be concerned about the possibility of military force and are taking a more cautious and reconciliatory approach. I think the North Koreans are well aware that militaristic posturing won't get them very far with Trump the way it did with past presidents.