When certifi is available, pass its CA bundle path as --ca-certificate to the aria2c subprocess so that aria2 downloads use the same certificate store as Python aiohttp downloads. Graceful fallback when certifi is not installed.
When certifi is available, pass its CA bundle path as --ca-certificate to the aria2c subprocess so that aria2 downloads use the same certificate store as Python aiohttp downloads. Graceful fallback when certifi is not installed.