Add scala 3 to spray json matrix for v3 client

[MichelEdkrantz]

Before submitting pull request:

• [x] Check if the project compiles by running sbt compile
• [x] Verify docs compilation by running sbt compileDocs
• [x] Check if tests pass by running sbt test
• [ ] Format code by running sbt scalafmt

Same as #2181 but for v3 client.

[adamw]

thanks :)