allow allow_from_override

[r3mi]

Description

Hello,
thanks for this useful container !
In my current setting, I would like to force the "From" field in all emails (due to restrictions by the SMTP relay of my ISP).
However, setting SMTP_FROM and SMTP_SET_FROM_HEADER=on does not work, my emails "from" is not forced to SMTP_FROM.
If I understand correctly the msmtp docs, it seems I also need to disable allow_from_override.
Is it possible to give access to that option ?