Unconditionally support 128-bit integers

Always supported on modern rust & avoids a deprecation warning in slog v2.8.
See slog-rs/slog@48e4651 for details.

This change has no affect on behavior and does not fix a bug,
so does not need to be noted in the changelog.

Author: Techcable

src/lib.rs

@@ -1,4 +1,4 @@
-// {{{ Crate docs
+//! {{{ Crate docs
 //! JSON `Drain` for `slog-rs`
 //!
 //! ```
@@ -23,7 +23,6 @@
 extern crate slog;
 
 use serde::ser::SerializeMap;
-use serde::serde_if_integer128;
 use slog::Key;
 use slog::Record;
 use slog::{FnValue, PushFnValue};
@@ -132,13 +131,11 @@ where
     fn emit_f64(&mut self, key: Key, val: f64) -> slog::Result {
         impl_m!(self, key, &val)
     }
-    serde_if_integer128! {
-        fn emit_u128(&mut self, key: Key, val: u128) -> slog::Result {
-            impl_m!(self, key, &val)
-        }
-        fn emit_i128(&mut self, key: Key, val: i128) -> slog::Result {
-            impl_m!(self, key, &val)
-        }
+    fn emit_u128(&mut self, key: Key, val: u128) -> slog::Result {
+        impl_m!(self, key, &val)
+    }
+    fn emit_i128(&mut self, key: Key, val: i128) -> slog::Result {
+        impl_m!(self, key, &val)
     }
     fn emit_str(&mut self, key: Key, val: &str) -> slog::Result {
         impl_m!(self, key, &val)