ruma-events: Add the new key agreement method.

ruma-events/src/key/verification.rs

@@ -25,11 +25,13 @@ pub enum HashAlgorithm {
 /// A key agreement protocol.
 #[derive(Clone, Copy, Debug, PartialEq, Display, EnumString, Serialize, Deserialize)]
 #[non_exhaustive]
-#[serde(rename_all = "snake_case")]
-#[strum(serialize_all = "snake_case")]
+#[serde(rename_all = "kebab-case")]
+#[strum(serialize_all = "kebab-case")]
 pub enum KeyAgreementProtocol {
     /// The [Curve25519](https://cr.yp.to/ecdh.html) key agreement protocol.
     Curve25519,
+    /// The Curve25519 key agreement protocol with check for public keys.
+    Curve25519HkdfSha256,
 }
 
 /// A message authentication code algorithm.