Refine release pipeline

[shizhMSFT]

This issue to track the enhancement on auto releasing oras when a new version is cut.

The current release pipeline requires lots of manual steps and personal credentials. Instead of personal credentials, we can leverage GITHUB_TOKEN for releases. An example can be found in the notation repo. Similarly, GITHUB_TOKEN can be used to release packages to ghcr.io according this guide.

Before having a new release, it is better to revisit the following issues:

• Multi-arch docker image #373
• Could it be possible to add 32 bits binaries? #364
• Docker image releases with different Go version than binaries #251

Related issues:

• Create an ORAS Release Checklist #256

Successor issues:

• Fix up the release checklist for CLI oras-www#10

[qweeah]

Ack