Bump actions/checkout from 2.3.4 to 2.4.0 (#95)

Bumps [actions/checkout](https://github.com/actions/checkout) from 2.3.4 to 2.4.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2.3.4...v2.4.0)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Christian Banse <[email protected]>

Fixed Docker entrypoint and adjusted README (#33)

Fixed ghcr.io

Fixed ghcr.io

Hotfix for #30 (#31)

Improved CI building (#29)

* Cross-Compilation only for CI
* Better names for executable names to avoid conflicts in GH releases

use go 1.16 embed

Objective tracking is now persisted. Fixes #3