Bump Fronter.NET from 55ecee7 to 709e908

Bumps [Fronter.NET](https://github.com/ParadoxGameConverters/Fronter.NET) from `55ecee7` to `709e908`.
- [Commits](ParadoxGameConverters/Fronter.NET@55ecee7...709e908)

---
updated-dependencies:
- dependency-name: Fronter.NET
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>