As this very old post shows, audio time remapping has not been an option when working with Premiere Pro, making the process of speed ramping videos with audio (or even audio by itself) not possible within the software.
This very simple feature is already present in After Effect and even Premiere Rush, but still requires you to move to AE or AU to do it when working on Premiere Pro.
Would be very useful for our workflow to get a "Time remap audio too" checkbox when time remapping a clip, or better yet making time remapping of an audio clip possible and available by right clicking the fx square on an audio clip.