Support the upload-artifact `overwrite` option.

[akostadinov]

I'm getting [1]

Error: Failed to CreateArtifact: Received non-retryable error: Failed request: (409) Conflict: an artifact with this name already exists on the workflow run

please support the overwrite upload-artifacts v4 option [2] to allow such uploads.

[1] https://github.com/akostadinov/websocket-echo-io/actions/runs/12507938287/job/34895293456
[2] https://github.com/actions/download-artifact/blob/main/docs/MIGRATION.md