Add automated release workflow

[BowTiedRadone]

This PR adds a GitHub Actions workflow to automate the release process for the Hedgehog library. Key features:

• Builds and packages the Hedgehog library using the latest GHC and cabal-install via GHCup.
• Uses cabal sdist to generate the tarball matching maintainer/Hackage requirements.
• Checks the package with cabal check before upload.
• Uploads the tarball to Hackage using a repository secret (HACKAGE_TOKEN).
• Only triggers on new tags.

Notes

The workflow expects a valid HACKAGE_TOKEN secret to be set in the repository for Hackage uploads. The tarball creation logic is designed to match the official Hackage release process as closely as possible.

Considerations

The new workflow's output was tested locally using act and diff-checked agains the latest official Hackage release. This PR should be merged after one of the maintainers can confirm the HACKAGE_TOKEN secret addition.