Docs: Adding Package Repository Permissions to permissions.md

What does this MR do?

Adds package repository permission information to the permissions.md file

• Pull from Private Package Repository
• Publish to Package Repository

Author's checklist

• Apply the correct labels and milestone
• Correctly apply the product badges and tiers
• Port the MR to EE (or backport from CE): always recommended, required when the ee-compat-check job fails

Review checklist

• Your team's review (required)
• PM's review (recommended, but not a blocker)
• Technical writer's review (required)
• Merge the EE-MR first, CE-MR afterwards