Added debug=2 in release profile to all examples.

This makes rtt output work right when using `cargo run` in release mode.

Debug was already enabled for release builds in some of the examples but
not all.

examples/nrf52840-rtic/Cargo.toml

@@ -19,3 +19,6 @@ cortex-m = { version = "0.7.6", features = ["inline-asm", "critical-section-sing
 cortex-m-rt = "0.7.0"
 panic-probe = { version = "0.3", features = ["print-defmt"] }
 futures = { version = "0.3.17", default-features = false, features = ["async-await"] }
+
+[profile.release]
+debug = 2