Add categories to crates.io metadata

serde/Cargo.toml

@@ -3,7 +3,7 @@ name = "serde"
 version = "1.0.140" # remember to update html_root_url and serde_derive dependency
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 build = "build.rs"
-categories = ["encoding"]
+categories = ["encoding", "no-std"]
 description = "A generic serialization/deserialization framework"
 documentation = "https://docs.serde.rs/serde/"
 homepage = "https://serde.rs"