You are using staging server - a separate instance of the ESP Component Registry that allows you to try distribution tools and processes without affecting the real registry.
# BSP: ESP32-Azure-IoT-Kit Board support package consists of: * uSD card interface * I2C interface * LEDs, button and buzzer interface
idf.py add-dependency "espressif/esp32_azure_iot_kit^0.0.3-alpha"