Bump version to 0.4.0

Signed-off-by: Daniel Egger <daniel@eggers-club.de>

Author: therealprof

Cargo.toml

@@ -15,7 +15,7 @@ keywords = [
 license = "0BSD"
 name = "stm32f407g-disc"
 repository = "https://github.com/stm32-rs/stm32f407g-disc"
-version = "0.3.0"
+version = "0.4.0"
 readme = "README.md"
 
 [dependencies]