Is there a risk of exposing my mac address by using this script?
the script explicitly sets the access point's mac address as the "source" mac address when sending spoofed packets, see the ap_mac and how it's used when crafting the RadioTap() layers:
https://github.com/flashnuke/wifi-deauth/blob/main/wifi_deauth/wifi_deauth.py#L284
https://github.com/flashnuke/wifi-deauth/blob/main/wifi_deauth/wifi_deauth.py#L297
https://github.com/flashnuke/wifi-deauth/blob/main/wifi_deauth/wifi_deauth.py#L307
in other words what this means is that instead of your mac address, these packets contain the target access point's mac address, so there should be no risk of exposing yours
however if that's important to you, you can use a 3rd party tool such as macchanger to spoof your device's mac address, just be sure you use it on the right network interface