Fix: Avoid deprecation warnings esptool/pythonx

[petermm]

Since pythonx/esptool is version locked 5.0.2 we are certain we are esptool version 5+, and can use the renamed options(sic!)

Avoids confusing warnings:

Flashing using Pythonx installed esptool..
Warning: Deprecated: Option '--flash_mode' is deprecated. Use '--flash-mode' instead.
Warning: Deprecated: Option '--flash_freq' is deprecated. Use '--flash-freq' instead.
Warning: Deprecated: Option '--flash_size' is deprecated. Use '--flash-size' instead.
Warning: Deprecated: Choice 'default_reset' for option '--before' is deprecated. Use 'default-reset' inste
ad.
Warning: Deprecated: Choice 'hard_reset' for option '--after' is deprecated. Use 'hard-reset' instead.
Warning: Deprecated: Command 'write_flash' is deprecated. Use 'write-flash' instead.
esptool v5.0.2
Connected to ESP32-S2 on /dev/ttyACM0:
Chip type: ESP32-S2FNR2 (revision v1.0)
...