A hackathon event is pushing the US Army and defense partners to better integrate systems.US Army photo by Sgt. Nicodemus TaylorThe US Army and industry partners are making drones, sensors, and weapons talk to one another.Decades-old barriers prevented systems from connecting, forcing personnel to be the link.Lessons from Ukraine and the Army's new warfighting software have inspired the changes.US Army leaders are trying to break down the decade…