🏷️ Add labels to Earthfile

[robinschneider]

Add labels org.opencontainers.image.source and org.opencontainers.image.revision to Earthfile.
This will allow renovate to find release notes for PRs.

[robinschneider]

Tested with earthly +ci
docker image inspect ghcr.io/stackitcloud/yawol/yawol-controller:yawol-controller-0.21.3-15-g8ec7594

"Labels": {
                "dev.earthly.built-by": "homebrew-earthly",
                "dev.earthly.git-sha": "e77372274b09b5e5f8a42f1b6ac264f7149c4924",
                "dev.earthly.version": "v0.7.23",
                "org.opencontainers.image.revision": "8ec7594a27a01d6c184db71cc06a5fef8ea42790",
                "org.opencontainers.image.source": "https://github.com/stackitcloud/yawol"
            }

[Kumm-Kai]

Thanks 🙂

We've decided to drop BUILD +set-version and it doesn't seem to be needed, but maybe someone else knows if we can really drop it.

[hown3d]

BUILD +set-version could be used to set the label org.opencontainers.image.version

[robinschneider]

BUILD +set-version could be used to set the label org.opencontainers.image.version

Added it as well