This reverts commit da8e4b2.

When running go build -o concourse ./cmd/concourse we'd get this error:

# k8s.io/apimachinery/pkg/util/managedfields/internal
../../../go/pkg/mod/k8s.io/apimachinery@v0.30.0/pkg/util/managedfields/internal/structuredmerge.go:56:4: unknown field IgnoredFields in struct literal of type merge.Updater
../../../go/pkg/mod/k8s.io/apimachinery@v0.30.0/pkg/util/managedfields/internal/structuredmerge.go:73:4: unknown field IgnoredFields in struct literal of type merge.Updater

Seems like go isn't following the dependency path correctly. k8s.io/apimachinery@v0.30.0 uses sigs.k8s.io/structured-merge-diff/v4@v4.4.1 in it's go.mod but it appears when building go decides to use v4.4.2 of that package where the IgnoredFields field is gone. Unblocking pipeline by reverting this deps bump for now.