bottom-nightly: Fix checkver branch

[brian6932]

I mixed up GH's workflows and commits APIs :P, bottom renamed their default branch from master to main.

• [x] I have read the Contributing Guide.

[github-actions[bot]]

Your changes do not pass checks.

bottom-nightly

• [x] Description
• [x] License
• [ ] Hashes
• [ ] Checkver
• [x] Autoupdate

freac-continuous

• [x] Description
• [x] License
• [x] Hashes
• [x] Checkver
• [x] Autoupdate

prismlauncher-git

• [x] Description
• [x] License
• [x] Hashes
• [ ] Checkver
• [ ] Autoupdate

strawberry-nightly

• [x] Description
• [x] License
• [x] Hashes
• [x] Checkver
• [x] Autoupdate

[brian6932]

/verify

[github-actions[bot]]

All changes look good.

Wait for review from human collaborators.

bottom-nightly

• [x] Description
• [x] License
• [x] Hashes
• [x] Checkver
• [x] Autoupdate