fix: slack token missing bearer prefix

[SimeonC]

Authorization failed due to incorrectly formatted header. Documentation reference: https://api.slack.com/web#slack-web-api__basics__post-bodies__json-encoded-bodies

[juliuscc]

Hmm, do you know why this hasn't been a problem before? Just so I know that we don't merge something incorrect by mistake.

Are you using some new features like the new token system? Or do the other users include "Bearer " as a prefix in their token?

[SimeonC]

Probably because I haven't managed to use it since I originally subitted the feature 😅. I succumbed to the "I read the documentation and this all looks correct" temptation and didn't actually test out a proper release run with my previous PR 🤦. The usage is a little bit weird as if you use the octocat sdk (which I have been elsewhere) you don't need to add the bearer token and I assumed it was the same here - until I dug into the docs when it all failed today (crushing my confidence along the way).
Had a lot of other work issues crop up and some blockers from our infrastructure team that I hadn't actually tried out the feature in a release pipeline till today.

[juliuscc]

Okay, that makes sense to me. It explains why the webhook users haven't had any issues.

[juliuscc]

🎉 This PR is included in version 3.4.1 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀

[SimeonC]

Awesome! Thanks for the quick release ✨