bpo-26510: Add versionchanged for required arg of add_subparsers (GH-16588)


The `required` argument to `argparse.add_subparsers` was added in GH-3027. This PR specifies the earliest version of Python where it is available.

https://bugs.python.org/issue26510

Automerge-Triggered-By: @merwok
(cherry picked from commit 9e71917e0290972f65711f75510078f799cf0b59)

Co-authored-by: Adam J. Stewart <ajstewart426@gmail.com>
2 files changed