Release v0.19.0

• Signing via pubtools-sign
• Instrument tracing for container push by @zxiong in #201
• Add static typing to pubtools-quay by @querti in #203
• Add option to disable sending transparency logs to rekor by @querti in https://github.com/release-engineering/pubtools-
• Full Changelog: v0.18.0...v0.19.0