chore: enable to upload file without channel param

[nakamasato]

Pull Request Guidelines

These are recommendations for pull requests. They are strictly guidelines to help manage expectations.

PR preparation

Run make pr-prep from the root of the repository to run formatting, linting and tests.

Should this be an issue instead

• [ ] is it a convenience method? (no new functionality, streamlines some use case)
• [ ] exposes a previously private type, const, method, etc.
• [ ] is it application specific (caching, retry logic, rate limiting, etc)
• [ ] is it performance related.

API changes

Since API changes have to be maintained they undergo a more detailed review and are more likely to require changes.

• no tests, if you're adding to the API include at least a single test of the happy case.
• If you can accomplish your goal without changing the API, then do so.
• dependency changes. updates are okay. adding/removing need justification.

Examples of API changes that do not meet guidelines:

• in library cache for users. caches are use case specific.
• Convenience methods for Sending Messages, update, post, ephemeral, etc. consider opening an issue instead.

Ref

• https://api.slack.com/methods/files.completeUploadExternal

[0xdeafcafe]

Anything I can do to help push this through? Would be really useful for us.

[nakamasato]

@0xdeafcafe Thanks!I wanted to upload a file without sending out to the channel but after roughly checking the API, i'm not very sure if it's possible from the api perspective and kept my pr draft. I saw you already made your own PR. Let's see there!

[0xdeafcafe]

@0xdeafcafe Thanks!I wanted to upload a file without sending out to the channel but after roughly checking the API, i'm not very sure if it's possible from the api perspective and kept my pr draft. I saw you already made your own PR. Let's see there!

We're using a fork of the repo with my PR on production at the moment, so I can confirm it works thankfully.