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/stm32c0/Cargo.toml

@@ -20,3 +20,6 @@ embedded-hal = "0.2.6"
 panic-probe = { version = "0.3", features = ["print-defmt"] }
 futures = { version = "0.3.17", default-features = false, features = ["async-await"] }
 heapless = { version = "0.7.5", default-features = false }
+
+[profile.release]
+debug = 2