Order repository tags in dropdowns according to Semantic Versioning

Description

Tags are sorted alphabetically (rather than SemVer) in the dropdown list which also allows for selecting a specific branch. Observed for this project: https://gitlab.com/ase/ase

![gitlab-sorting-issue](/uploads/8c2b65a2944878f4e7fbab9e18c38000/gitlab-sorting-issue.png)

Proposal

When tags adhere to semantic versioning, sort the tags in SemVer order rather than alphabetical order in the dropdown menus

Links / references

• http://semver.org/