esp32: ignore new generated files

Ignore generated files in recent versions of the ESP32 Arduino core.

esp32/.gitignore

@@ -11,3 +11,7 @@ cache/
 *.map
 www/version
 max80/src/common
+max80/debug.cfg
+max80/debug_custom.json
+max80/esp32s2.svd
+max80/sketch.yaml