Add branch and semantic version tags to Docker image workflow

[kusssal]

List of changes

• Add rolling Docker image tags for main, develop, and test.
• Add semantic-version tags such as v2.1.2, v2.1, and v2.

Checklist

• My changes generate no new warnings
• My code follows the [style guidelines](https://github.com/IntersectMBO/govtool/tree/main/docs/style-guides) of this project
• I have commented my code, particularly in hard-to-understand areas
• Changelog update is not required for this CI-only change
• Automated tests are not applicable; the workflow will be verified through branch and version-tag builds