fix serde support (#366)

Author: Byron

git-attributes/src/ignore.rs

@@ -2,6 +2,7 @@ pub mod pattern {
     use bitflags::bitflags;
 
     bitflags! {
+        #[cfg_attr(feature = "serde1", derive(serde::Serialize, serde::Deserialize))]
         pub struct Mode: u32 {
             /// The pattern does not contain a sub-directory and - it doesn't contain slashes after removing the trailing one.
             const NO_SUB_DIR = 1 << 0;

git-attributes/src/lib.rs

@@ -1,4 +1,5 @@
-#![forbid(unsafe_code, rust_2018_idioms)]
+#![forbid(unsafe_code)]
+#![deny(rust_2018_idioms)]
 
 use bstr::BStr;
 
@@ -11,6 +12,7 @@ pub enum State<'a> {
     Unset,
     /// The attribute is set to the given value, which followed the `=` sign.
     /// Note that values can be empty.
+    #[cfg_attr(feature = "serde1", serde(borrow))]
     Value(&'a BStr),
     /// The attribute isn't mentioned with a given path or is explicitly set to `Unspecified` using the `!` sign.
     Unspecified,

git-mailmap/src/lib.rs

@@ -1,4 +1,5 @@
-#![forbid(unsafe_code, rust_2018_idioms)]
+#![forbid(unsafe_code)]
+#![deny(rust_2018_idioms)]
 
 use bstr::BStr;
 
@@ -12,6 +13,7 @@ mod entry;
 #[derive(PartialEq, Eq, Debug, Hash, Ord, PartialOrd, Clone, Default)]
 #[cfg_attr(feature = "serde1", derive(serde::Serialize, serde::Deserialize))]
 pub struct Entry<'a> {
+    #[cfg_attr(feature = "serde1", serde(borrow))]
     /// The name to map to.
     canonical_name: Option<&'a BStr>,
     /// The email map to.