Serde update is a breaking change

Author: SimonSapin

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 
 name = "string_cache"
-version = "0.5.2"  # Also update README.md when making a semver-breaking change
+version = "0.6.0"  # Also update README.md when making a semver-breaking change
 authors = [ "The Servo Project Developers" ]
 description = "A string interning library for Rust, developed as part of the Servo project."
 license = "MIT / Apache-2.0"

README.md

@@ -12,7 +12,7 @@ In `Cargo.toml`:
 
 ```toml
 [dependencies]
-string_cache = "0.5"
+string_cache = "0.6"
 ```
 
 In `lib.rs`: