Update build.func - fixed spelling mistake

[m1ckywill]

✍️ Description

Noted that the OS update prompt had a typo in 'Packages'. This only updates the printed text part of the prompt, no functionality changes.
Unsure of how to test this as I'm not building a script myself, and this seems to be a core part of the tooling for the project.
This is my first commit to a public repo - please let me know if I need to amend anything, and thanks for continuing tteck's legacy.

🔗 Related Issue

None - Hoping it's less burden if I fix the typo myself than raising a bug. But I appreciate it's my first PR so I'm hoping I'm not adding too much to maintainer burden.

Fixes #

✅ Prerequisites (X in brackets)

• Self-review completed – Code follows project standards.
• Tested thoroughly – Changes work as expected.
• No security risks – No hardcoded secrets, unnecessary privilege escalations, or permission issues.

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🛠️ Type of Change (X in brackets)

• 🐞 Bug fix – Resolves an issue without breaking functionality.
• ✨ New feature – Adds new, non-breaking functionality.
• 💥 Breaking change – Alters existing functionality in a way that may require updates.
• 🆕 New script – A fully functional and tested script or script set.
• 🌍 Website update – Changes to script metadata (PocketBase/website data).
• 🔧 Refactoring / Code Cleanup – Improves readability or maintainability without changing functionality.
• 📝 Documentation update – Changes to README, AppName.md, CONTRIBUTING.md, or other docs.

[MickLesk]

@michelroegl-brunner Always drunk