Yes I created this thread in order to get the arduino team to look into it. I did that because the library git has no issues thing.
Here is the original thread. Note post #3 in that thread and the comment re ESP32 vs 8266. The OP is using an 8266.
https://forum.arduino.cc/t/esp8266-sketch-compile-fail-on-spiffs-deprecated-warning/1319786