feat: unstable-json-schema generation for Cargo.toml

Author: dacianpascu06

crates/cargo-util-schemas/Cargo.toml

@@ -9,8 +9,10 @@ repository.workspace = true
 description = "Deserialization schemas for Cargo"
 
 [dependencies]
+schemars = { version = "0.8.21", features = ["preserve_order","semver"], optional = true }
 semver.workspace = true
 serde = { workspace = true, features = ["derive"] }
+serde_json = { version = "1.0", optional = true }
 serde-untagged.workspace = true
 serde-value.workspace = true
 thiserror.workspace = true
@@ -23,3 +25,6 @@ workspace = true
 
 [dev-dependencies]
 snapbox.workspace = true
+
+[features]
+unstable-schema = ["dep:schemars", "dep:serde_json"]