bump proxmox to 0.3, cleanup http_err macro usage

Also swap the order of a couple of `.map_err().await` to
`.await.map_err()` since that's generally more efficient.

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

src/api2/access.rs

@@ -156,7 +156,7 @@ fn create_ticket(
         Err(err) => {
             let client_ip = "unknown"; // $rpcenv->get_client_ip() || '';
             log::error!("authentication failure; rhost={} user={} msg={}", client_ip, username, err.to_string());
-            Err(http_err!(UNAUTHORIZED, "permission check failed.".into()))
+            Err(http_err!(UNAUTHORIZED, "permission check failed."))
         }
     }
 }