Update defmt-rtt requirement from 0.3 to 0.4

Updates the requirements on [defmt-rtt](https://github.com/knurling-rs/defmt) to permit the latest version.
- [Release notes](https://github.com/knurling-rs/defmt/releases)
- [Changelog](https://github.com/knurling-rs/defmt/blob/main/CHANGELOG.md)
- [Commits](knurling-rs/defmt@defmt-rtt-v0.3.0...defmt-rtt-v0.4.0)

---
updated-dependencies:
- dependency-name: defmt-rtt
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

esp32-wroom-rp/Cargo.toml

@@ -24,7 +24,7 @@ cortex-m-semihosting = "0.5"
 embedded-hal = { version = "0.2", features=["unproven"] }
 
 defmt = "0.3"
-defmt-rtt = "0.3"
+defmt-rtt = "0.4"
 heapless = "0.7.16"
 panic-probe = { version = "0.3", features = ["print-rtt"] }