docs: add link for refreshing Azure token

Description

Today I had to go and update the Azure token for publishing to MSFT marketplace because they expired today.

https://gitlab.com/gitlab-org/gitlab-vscode-extension/-/issues/815

I added a link to the docs because it took me a while to find the token settings.

How has this been tested

I successfully released https://gitlab.com/gitlab-org/gitlab-vscode-extension/-/jobs/5643353460

Screenshots (if appropriate):

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)
• Documentation
• Chore (Related to CI or Packaging to platforms)
• Test gap