DeepSpeed

c210e601 - Update version.txt after 0.15.1 release (#6493)

Update version.txt after 0.15.1 release (#6493) **Auto-generated PR to update version.txt after a DeepSpeed release** Released version - 0.15.1 Author - @loadams Co-authored-by: loadams <loadams@users.noreply.github.com>