Enables up to 3 retries of uploading a single asset when encountering a network error or a HTTP 5xx error.
Bonus:
- simplifies ConcurrentUpload implementation
- support Go context cancellation
Fixes https://github.com/cli/cli/issues/6566
When running `gh release create <tag> --verify-tag`, we query <tag>
among repository tags via the GitHub API before creating the release,
and abort the command if the tag was not found.
When publishing a release, we rely on server-side validation to abort the operation if an existing published release with the same tag name already exists.
However, then creating a release with assets, we first create a draft release, upload assets to it, then publish. If there was an existing release with the same tag name, the operation would fail but it would leave behind a temporary draft release with assets. This makes the operation fail earlier, before creating any records.
If `gh release create <TAG>` was called and TAG exists locally but not on the remote, this warns about the unpushed tag to avoid recreating it on the remote. The user can pass a value for `--target` to silence the warning.
Flag for signaling that a discussion should be created with the given
category for the release. Discussions are not supported for draft
releases. If a discussion category is given for a draft, an err will be
shown.
Closes#3381
