Added missing docs of Snap avatars max size etc.

Thanks to xet7 !

snap-src/bin/wekan-help

@@ -148,6 +148,24 @@ echo -e "\t$ snap set $SNAP_NAME attachments-upload-max-size='5000000'"
 echo -e "Disable, default:"
 echo -e "\t$ snap unset $SNAP_NAME attachments-upload-max-size"
 echo -e "\n"
+echo -e "Avatars upload validation by an external program. {file} is replaced by the uploaded file. Example: /usr/local/bin/avscan {file}"
+echo -e "Enable:"
+echo -e "\t$ snap set $SNAP_NAME avatars-upload-external-program='/usr/local/bin/avscan {file}'"
+echo -e "Disable, default:"
+echo -e "\t$ snap unset $SNAP_NAME avatars-upload-external-program"
+echo -e "\n"
+echo -e "Avatars upload mime types. Example: image/*,text/*"
+echo -e "Enable:"
+echo -e "\t$ snap set $SNAP_NAME avatars-upload-mime-types='image/*,text/*'"
+echo -e "Disable, default:"
+echo -e "\t$ snap unset $SNAP_NAME avatars-upload-mime-types"
+echo -e "\n"
+echo -e "Avatars upload max size in bytes. Example: 5000000"
+echo -e "Enable:"
+echo -e "\t$ snap set $SNAP_NAME avatars-upload-max-size='5000000'"
+echo -e "Disable, default:"
+echo -e "\t$ snap unset $SNAP_NAME avatars-upload-max-size"
+echo -e "\n"
 echo -e "Max image pixel: Allow to shrink attached/pasted image https://github.com/wekan/wekan/pull/2544"
 echo -e "Example:"
 echo -e "\t$ snap set $SNAP_NAME max-image-pixel='1024'"