Dagger 0.4: Service containers, secrets scrubbing, and more

Today's release of Dagger 0.4.0 introduces service containers, which enable the run of network services as ephemeral containers within a Dagger pipeline. This feature is particularly useful for running test databases, end-to-end integration tests, and sidecar services. Service containers are started just-in-time, de-duplicated, and stopped when no longer needed, with built-in features such as health checking and hostname aliasing. The release also includes secrets scrubbing, which automatically removes sensitive data from logs and output streams. Additionally, new versions of Dagger's SDKs have been released with support for the new features, along with various bug fixes and improvements.