feat!: add missing api key error

BREAKING CHANGE: `APIError` is renamed to `ApiError`.

tests/v1_client_list_models_test.rs

@@ -0,0 +1,20 @@
+use jrest::expect;
+use mistralai_client::v1::client::Client;
+
+#[test]
+fn test_client_list_models() {
+    let client = Client::new(None, None, None, None);
+
+    let response = client.list_models().unwrap();
+
+    expect!(response.object).to_be("list".to_string());
+    expect!(response.data.len()).to_be_greater_than(0);
+
+    // let open_mistral_7b_data_item = response
+    //     .data
+    //     .iter()
+    //     .find(|item| item.id == "open-mistral-7b")
+    //     .unwrap();
+
+    // expect!(open_mistral_7b_data_item.id).to_be("open-mistral-7b".to_string());
+}