#1603 Enable torch elastic training (torchrun) Pull request opened by fg91 TL;DR This PR brings torch elastic training (`torchrun`) to the pytorch plugin:

from flytekitplugins.kfpytorch import Elastic

@task(
    task_config=Elastic(
        replicas=4,
        nproc_per_node=4,
        ...
    ),
    ...
)
def train(...):
    ...

Type ☐ Bug Fix ☑︎ Feature ☐ Plugin Are all requirements met? ☑︎ Code completed ☑︎ Smoke tested ☑︎ Unit tests added ☑︎ Code documentation added ☑︎ Any pending items have an associated Issue Complete description See flyteorg/flyte#3614 for motivation and a more detailed description. Tracking Issue flyteorg/flyte#3614 Follow-up issue flyteorg/flytekit ✅ All checks have passed 30/30 successful checks