Build Image: Bump atc0005/go-ci from go-ci-oldstable-build-v0.21.5 to go-ci-oldstable-build-v0.21.6 in /dependabot/docker/builds

Build Image: Bump atc0005/go-ci from go-ci-oldstable-build-v0.21.5 to go-ci-oldstable-build-v0.21.6 in /dependabot/docker/builds #387