fix: prerelease logic clearer and more reliable

[b-zurg]

Trying to access releases on my github repository was not working and the logic behind prereleases was kind of confusing.

This simplifies that logic and makes it more reliable.

[vercel[bot]]

This pull request is being automatically deployed with Vercel (learn more). To see the status of your deployment, click below or on the icon next to each commit.

🔍 Inspect: https://vercel.com/zeit/hazel/nucz96yjm ✅ Preview: https://hazel-git-fork-b-zurg-fix-prerelease-logic.zeit.now.sh

[ricardodantas]

Hey @b-zurg! I would love to get this PR on Peanut.

[b-zurg]

As in to make this same PR for the repo. Sure.