Bump Rust edition and fix clippy lints

Cargo.toml

@@ -7,7 +7,7 @@ repository = "https://github.com/thombles/ax25-rs"
 keywords = ["amateur", "radio", "packet", "ham"]
 categories = ["network-programming"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 readme = "README.md"
 
 [dependencies]

src/frame.rs

@@ -742,7 +742,7 @@ fn test_round_trips() {
                 // Should be identical when re-encoded
                 assert_eq!(frame_data_fixed, &parsed.to_bytes()[..])
             }
-            Err(e) => assert!(false, "Could not parse! {}", e),
+            Err(e) => panic!("Could not parse! {}", e),
         };
     }
 }

src/tnc.rs

@@ -162,8 +162,8 @@ impl Tnc {
     /// Attempt to obtain a `Tnc` connection using the provided address.
     pub fn open(address: &TncAddress) -> Result<Self, TncError> {
         let imp: Box<dyn TncImpl> = match &address.config {
-            ConnectConfig::TcpKiss(config) => Box::new(TcpKissTnc::open(&config)?),
-            ConnectConfig::LinuxIf(config) => Box::new(LinuxIfTnc::open(&config)?),
+            ConnectConfig::TcpKiss(config) => Box::new(TcpKissTnc::open(config)?),
+            ConnectConfig::LinuxIf(config) => Box::new(LinuxIfTnc::open(config)?),
         };
         Ok(Tnc(Arc::new(Mutex::new(TncInner::new(imp)))))
     }
@@ -367,18 +367,14 @@ mod test {
                 })
             })
         );
-        assert!(match "fish".parse::<TncAddress>() {
-            Err(ParseError::NoTncPrefix { .. }) => true,
-            _ => false,
-        });
-        assert!(match "tnc:".parse::<TncAddress>() {
-            Err(ParseError::UnknownType { tnc_type }) => tnc_type == "",
-            _ => false,
-        });
-        assert!(match "tnc:fish".parse::<TncAddress>() {
-            Err(ParseError::UnknownType { tnc_type }) => tnc_type == "fish",
-            _ => false,
-        });
+        assert!(matches!(
+            "fish".parse::<TncAddress>(),
+            Err(ParseError::NoTncPrefix { .. })
+        ));
+        assert!(matches!("tnc:".parse::<TncAddress>(),
+            Err(ParseError::UnknownType { tnc_type }) if tnc_type.is_empty()));
+        assert!(matches!("tnc:fish".parse::<TncAddress>(),
+            Err(ParseError::UnknownType { tnc_type }) if tnc_type == "fish"));
         assert!(match "tnc:tcpkiss".parse::<TncAddress>() {
             Err(ParseError::WrongParameterCount {
                 tnc_type,