Setting up GitHub actions secrets

To set up secrets in order for the build actions workflow in astropy-tutorials to successfully execute, do the following.

1. In the astropy GitHub organization, create a fine-grained personal access token with:

a) 'Repository access' to both astropy-tutorials and learn-astropy

b) 'Organization permissions':

• Access to organization secrets (read/write)

c) 'Repository permissions' (for both astropy-tutorials and learn-astropy):

• Access to metadata (read)
• Access to secrets (read/write)
• "Contents" repository permissions (write)
• "Actions" repository permissions (write)

2. Create a secret in astropy-tutorials named DISPATCH_GITHUB_TOKEN (if it exists, update it with the new token value).