Switch serde dependency to serde_core

Author: dtolnay

Cargo.toml

@@ -13,7 +13,8 @@ repository = "https://github.com/serde-rs/example-format"
 rust-version = "1.61"
 
 [dependencies]
-serde = "1"
+serde_core = "1"
 
 [dev-dependencies]
+serde = "1"
 serde_derive = "1"

src/lib.rs

@@ -6,6 +6,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+extern crate serde_core as serde;
+
 mod de;
 mod error;
 mod ser;