admin api: specify date-time format in openapi spec

doc/api/garage-admin-v2.json

@@ -2053,6 +2053,7 @@
               "string",
               "null"
             ],
+            "format": "date-time",
             "description": "Expiration time and date, formatted according to RFC 3339"
           },
           "expired": {
@@ -3639,6 +3640,7 @@
               "string",
               "null"
             ],
+            "format": "date-time",
             "description": "Expiration time and date, formatted according to RFC 3339"
           },
           "name": {

src/api/admin/api.rs

@@ -317,7 +317,7 @@ pub struct GetAdminTokenInfoResponse {
 	/// Name of the admin API token
 	pub name: String,
 	/// Expiration time and date, formatted according to RFC 3339
-	#[schema(value_type = Option<String>)]
+	#[schema(value_type = Option<String>, format = DateTime)]
 	pub expiration: Option<chrono::DateTime<chrono::Utc>>,
 	/// Whether this admin token is expired already
 	pub expired: bool,
@@ -357,7 +357,7 @@ pub struct UpdateAdminTokenRequestBody {
 	/// Name of the admin API token
 	pub name: Option<String>,
 	/// Expiration time and date, formatted according to RFC 3339
-	#[schema(value_type = Option<String>)]
+	#[schema(value_type = Option<String>, format = DateTime)]
 	pub expiration: Option<chrono::DateTime<chrono::Utc>>,
 	/// Scope of the admin API token, a list of admin endpoint names (such as
 	/// `GetClusterStatus`, etc), or the special value `*` to allow all