[dbpolito]

Supersedes #78: the v5 action requires username/password inputs, so updating only the action version leaves the environment-only configuration broken.

• Upgrade to v5.0.0 and pass username, password and repository through with, matching the v5 contract and usage documentation.
• Keep existing secrets, repository, master-only path-filtered trigger and all other defaults unchanged.

The changed workflow passes actionlint and git diff --check. Contract validation was read-only; the description action was not executed and no Docker Hub description was published.

[dbpolito]

Validation correction: upstream v5.0.0 still supports the previous DOCKERHUB_* environment fallbacks. This merged update makes the configuration explicit via with: inputs; it was not necessary solely to preserve v5 environment compatibility and is not proof of fixing Docker Hub authentication. Actual description-sync success must be established by the post-merge workflow, separately from image publication.