diff --git a/ci/arduino-cli.yaml b/ci/arduino-cli.yaml
index 86a9c7d..a140639 100644
--- a/ci/arduino-cli.yaml
+++ b/ci/arduino-cli.yaml
@@ -1,3 +1,3 @@
 board_manager:
   additional_urls:
-    - https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json
+    [https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json]