acme/auth-api: add Default for types with un-parameterized new()

this fixes a clippy lint for types that have a `new()` function that
has no parameters [1]. this should allow using these types with
functions such as `unwrap_or_default()`.

[1]:
https://rust-lang.github.io/rust-clippy/master/index.html#new_without_default

Signed-off-by: Shannon Sterz <s.sterz@proxmox.com>

proxmox-acme/src/types.rs

@@ -38,6 +38,12 @@ pub enum AccountStatus {
     Revoked,
 }
 
+impl Default for AccountStatus {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl AccountStatus {
     /// Create a new instance with state New.
     #[inline]

proxmox-auth-api/src/auth_key.rs

@@ -237,6 +237,12 @@ pub struct Keyring {
     public_keys: Vec<VerificationKey>,
 }
 
+impl Default for Keyring {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl Keyring {
     pub fn generate_new_rsa() -> Result<Self, Error> {
         PrivateKey::generate_rsa().map(Self::with_private_key)