Connecting PT100 to Sonoff S55

I have installed Tasmota 8.3.1 to a Sonoff S55. This device has no obvious GPIO14 connection, but Rx, Tx, Vcc and Gnd are easily available. First off, i’m not sure how to connect this sensor as it’s only 2-wire, and what i can find with my google skills is 3-wires. Should i connect it between Rx and Vcc or Gnd? Should i add a 4,7kΩ pull-up between Rx and Vcc (Or Gnd)?

When the hardware is correct, am i only suppose to change GPIO3 Serial In to DS18x20 (4)?

EDIT: I have it setup as a Sonoff Basic as the S55 isn’t included in the default set.