Add unleash provider

[jarebudev]

Add unleash provider

Reasoning

I want to add an OpenFeature provider for unleash. This would be valuable because...

• unleash is a popular open-source feature flag solution
• can also use Gitlab as a flag provider for the JS SDK (Gitlab feature flagging uses an unleash compatible API)

Requirements:

• generate provider via tooling
• implement Provider interface
• add tests
• complete README
• add the new provider to the OpenFeature docs

Resources

• {useful-link}

Keep in mind the CONTRIBUTING guidelines: https://github.com/open-feature/js-sdk-contrib/blob/main/CONTRIBUTING.md

[jarebudev]

I've started looking at contributing this.

I have a (very) rough implementation that I've tested locally. This uses the JS unleash proxy client
https://docs.getunleash.io/reference/sdks/javascript-browser

I will tidy this up then share what I've got so far as it would be good to get feedback from the community on what I've done before I proceed further.