Add access-token option

[mems]

Description

Add --access-token option to provide directly an access token.

Related Issue

See #63

See also #64:

After an internal discussion on your proposed change, we'd prefer to accept the --access-token as a raw string value

— comment of Brent Hosie

Motivation and Context

Provide the access-token directly is a requirement to use OAuth Server-to-Server credential, since Service Account (JWT) credentials have been deprecated.

How Has This Been Tested?

Tested with unit test

Screenshots (if appropriate):

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

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

[brenthosie]

@mems npm install @adobe/auth-token@next has support for the new oauth-server-to-server standard. Does that meet your need?

[brenthosie]

Thank you for your contribution. Handled by #66 . See v6.0.0-beta.12.