chore: ensure that .cargo config is not published

Just in case, so the correct changelog will be rendered when pulling
the crate from the crates.io as archive and trying to build it.

Cargo.toml

@@ -14,6 +14,7 @@ rust-version.workspace = true
 repository.workspace = true
 license.workspace = true
 edition.workspace = true
+exclude = ["/.cargo"]
 
 [package.metadata.docs.rs]
 features = [