v0.12.13 : untagged unions

Highlights

• untagged unions are now supported in the simpleRestJson protocol, via the smithy4s.api#untagged shape. This encoding for unions should be discouraged, as it implies an attempt to decode
• fixes a bug where hints applied to union members would not be taken into consideration
• avoids serialising an empty object for requests that are not supposed to have body components

What's Changed

• Support untagged union by @daddykotex in #178
• Update/jsoniter scala core 2.13.13 by @daddykotex in #179
• Update jsoniter-scala-core to 2.13.13 by @scala-steward in #175
• Update smithy-model to 1.21.0 by @scala-steward in #183
• Update smithy-aws-traits, smithy-build, ... to 1.21.0 by @scala-steward in #182
• Union member fix by @Baccata in #186
• Update sbt-scalafix to 0.10.0 by @scala-steward in #170
• http4s make body empty when metadata is total by @lewisjkl in #171

Full Changelog: v0.12.12...v0.12.13