fix: update score-go library to fix metadata fields

[astromechza]

This PR brings in a fix from the score-go library: score-spec/score-go#25

This means we still have access to extended metadata fields in the workload spec, and workload resource.

The impact of this is low in this library, because other metadata fields were being ignored and not used anyway, however this keeps us up to date tracking the head of the library for any future changes.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• New chore (expected functionality to be implemented)

Checklist:

• My change requires a change to the documentation.
  • I have updated the documentation accordingly.
• I've signed off with an email address that matches the commit author.