Cache iOS build artifacts in GitHub Actions

[tomekzaw]

Description

This PR significantly shortens iOS app build times on CI by caching node_modules, Pods and DerivedData directories from ~25 minutes for Example app and ~45 minutes for FabricExample app down to ~8 and ~12 minutes, respectively.

Additionally, on macos-latest (alias of macos-11), the error "kLSNoExecutableErr: The executable is missing" appears in approximately 80% of the builds. The error disappears when using macos-12. For more details, check out this document.

Before:

After:

Changes

Test code and steps to reproduce

Checklist

• [ ] Included code example that can be used to test this change
• [ ] Updated TS types
• [ ] Added TS types tests
• [ ] Added unit / integration tests
• [ ] Updated documentation
• [ ] Ensured that CI passes