better solution for invalid US-100 readings

[vladak]

There is a workaround for https://forums.adafruit.com/viewtopic.php?p=1002731 in place and there is a fix on the way, however it might be more robust to use the HC-SR04 compatibility mode, i.e. resoldering needed.

[vladak]

Also, adafruit/circuitpython#8887 was closed as not a bug.

[vladak]

adafruit/Adafruit_CircuitPython_US100#19 has been opened yesterday which fixes the problem. adafruit_us100 release 1.1.17 should contain the fix.