Add a Hackage Auth Token as a repository secret

[sol]

Hi @JustusAdam, PR #72 sets up automated Hackage uploads via GitHub Actions.
To complete the setup, could you please take the following steps to add a Hackage authentication token as a repository secret? I don’t have the required permissions to do this myself.

Step 1: Generate a Hackage Auth Token

1. Go to https://hackage.haskell.org/users/account-management
2. Sign in with your Hackage credentials
3. Generate a new token under Authentication Tokens → Register new token

Step 2: Add the generated Hackage Auth Token to the GitHub repository

1. Go to https://github.com/JustusAdam/mustache/settings/secrets/actions/new
2. Use HACKAGE_AUTH_TOKEN as the Name and paste the generated token as the Secret
3. Click Add secret

[JustusAdam]

Done! Lmk if there are any issues.