add dummy test

To make sure tests in both crates run when calling `cargo test` in the
root dir.

rustls-cert-gen/src/main.rs

@@ -36,3 +36,8 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
 	fs::write("certs/key.der", &cert.serialize_private_key_der())?;
 	Ok(())
 }
+
+#[test]
+fn test_add() {
+	assert_eq!(1 + 1, 2)
+}