ci: configure release workflow to use trusted publishing

[galargh]

Description

This PR configures the release workflow to use trusted publishing. It is needed because NPM classic tokens (presumably used in this repository currently) are going to be deprecated in November.

Before this PR can be merged, package maintainer should configure trusted publishing on npmjs.org.

After this PR is merged, we can delete the NPM_TOKEN secret from the repository secrets.

How to configure trusted publishing on npmjs.org?

1. Go to https://www.npmjs.com/package/filsnap/access
2. Click on the GitHub Actions button in the Trusted Publishing section
3. Fill out the form with the following details:

• Organization: filecoin-project
• Repository: filsnap
• Workflow: release.yml

Link to issue

Please add a link to any relevant issues/tickets

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Refactor (non-breaking change that updates existing functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• Comments have been added/updated