make it build again

Cargo.toml

@@ -19,4 +19,4 @@ path = "src/bin.rs"
 
 [dependencies]
 "serial" = "0.4"
-err-derive = "0.1"
+err-derive = "0.3"

src/lib.rs

@@ -14,17 +14,6 @@ pub enum Error {
     CRC,
 }
 
-impl From<serial::Error> for Error {
-    fn from(err: serial::Error) -> Self {
-        Error::Serial(err)
-    }
-}
-
-impl From<std::io::Error> for Error {
-    fn from(err: std::io::Error) -> Self {
-        Error::IO(err)
-    }
-}
 
 pub type Result<T> = std::result::Result<T, Error>;