Add Auth variable in npmrc for publishing

[r48patel]

Description

Updating npmrc to include auth token reference

Related Issue

Error with releasing: https://github.com/adobe/commerce-events/actions/runs/25219667758

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)

Checklist

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.