curve: update repository in Cargo.toml (#575)

Point to the subdirectory which contains the crate

Author: tarcieri

curve25519-dalek/Cargo.toml

@@ -11,7 +11,7 @@ authors = ["Isis Lovecruft <[email protected]>",
            "Henry de Valence <[email protected]>"]
 readme = "README.md"
 license = "BSD-3-Clause"
-repository = "https://github.com/dalek-cryptography/curve25519-dalek"
+repository = "https://github.com/dalek-cryptography/curve25519-dalek/tree/main/curve25519-dalek"
 homepage = "https://github.com/dalek-cryptography/curve25519-dalek"
 documentation = "https://docs.rs/curve25519-dalek"
 categories = ["cryptography", "no-std"]