DeepSpeed

e93f0d16 - Update CONTRIBUTING.md to reflect changes from CLA to DCO (#7135)

Update CONTRIBUTING.md to reflect changes from CLA to DCO (#7135) Copy changes from https://github.com/deepspeedai/DeepSpeed-MII/pull/558. Fixes issue where docs still referenced CLA. --------- Signed-off-by: Logan Adams <loadams@microsoft.com>