Set up automated releases

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Set up automated semver releases using conventional commits.

See:

• https://github.com/marketplace/actions/laminas-automatic-releases
• https://github.com/laminas/automatic-releases

Specifically:

• https://github.com/laminas/automatic-releases/blob/1.25.x/examples/.github/workflows/release-on-milestone-closed.yml

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See also:

• https://docs.github.com/en/actions/deployment/targeting-different-environments/using-environments-for-deployment