Update cobs to 0.3.0

Author: musicinmybrain

source/postcard/Cargo.toml

@@ -36,7 +36,7 @@ default-features = false
 features = ["derive"]
 
 [dependencies.cobs]
-version = "0.2.3"
+version = "0.3.0"
 default-features = false
 
 [dependencies.defmt]