Update softprops/action-gh-release to version 2

[zorgiepoo]

Should fix:

Node.js 16 actions are deprecated. Please update the following actions to use Node.js 20: softprops/action-gh-release@v1. For more information see: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/

Misc Checklist

• My change requires a documentation update on Sparkle's website repository
• My change requires changes to generate_appcast, generate_keys, or sign_update

Testing

I tested and verified my change by using one or multiple of these methods:

• Sparkle Test App
• Unit Tests
• My own app
• Other (please specify)

I'll test this on this PR.