DeepSpeed

bf03f483 - Update version.txt after 0.15.3 release (#6652)

Update version.txt after 0.15.3 release (#6652) **Auto-generated PR to update version.txt after a DeepSpeed release** Released version - 0.15.3 Author - @jomayeri Co-authored-by: jomayeri <jomayeri@users.noreply.github.com>