Version number is a SHA, not "human readable" x.x.x

- Gitea version (or commit ref): 1.0.0 (6aacf4d)
- Can you reproduce the bug at https://try.gitea.io:
  - [X] Yes (provide example URL), all pages
  - [ ] No
  - [ ] Not relevant

## Description
Version number in the footer is a SHA instead of a human readable version number like 1.0.0