add rgb check and example

Cargo.toml

@@ -5,6 +5,8 @@ members = [
   "examples/button-input",
   "examples/embassy-blinky",
   "examples/embassy-button",
+  "examples/embassy-rgb-check",
+  "examples/embassy-rgb",
 ]
 resolver = "2"
 
@@ -22,3 +24,6 @@ embassy-time = "=0.5.1"
 nb = "=1.1.0"
 panic-probe = { version = "=1.0.0", features = ["print-defmt"] }
 stm32f1xx-hal = "=0.11.0"
+
+[profile.dev]
+opt-level = "s"