Giddy up, Los Angeles! Post Malone and Dwight Yoakam are bringing their cowboy ways to Hollywood! In a video obtained by TMZ from the celebrity gossip site Backgrid, the two country singers stroll down Sunset Boulevard at night, mouthing the words to what is likely an unreleased song from the pair. Both are wearing cowboy hats and snazzy, bedazzled jackets that sparkle in the streetlights. They pass the Roxy Theater, where the marquee reads, “Bang Bang Boom Boom! Dwight Yoakam featuring Post Malone.” In the background, a track of their vocals plays, and it sounds like they’re singing, “I never…