Use explicit Default for GzHeaderState enum

This allows the crate to build with Rust older than 1.62.

Author: jongiddy

src/gz/mod.rs

@@ -87,18 +87,23 @@ impl GzHeader {
     }
 }
 
-#[derive(Debug, Default)]
+#[derive(Debug)]
 pub enum GzHeaderState {
     Start(u8, [u8; 10]),
     Xlen(Option<Box<Crc>>, u8, [u8; 2]),
     Extra(Option<Box<Crc>>, u16),
     Filename(Option<Box<Crc>>),
     Comment(Option<Box<Crc>>),
     Crc(Option<Box<Crc>>, u8, [u8; 2]),
-    #[default]
     Complete,
 }
 
+impl Default for GzHeaderState {
+    fn default() -> Self {
+        Self::Complete
+    }
+}
+
 #[derive(Debug, Default)]
 pub struct GzHeaderParser {
     state: GzHeaderState,