[ci] nightly: add deepspeed master
We recently saw bugs introduced in Deepspeed master that were caught only on their new release. Which creates a gap in time where deepspeed integration doesn't work. To avoid that let's also test deepspeed master with the pytorch-nightly as there both pushing the bleeding edge.

Additionally this PR fixes the nightly pip install line that was misplaced originally. and pushes it first, before any other installs. Otherwise we end up first installing the current pytorch via dependencies of sub-packages, and then again the nightly.

@LysandreJik 