Configuration esphome mcp23017 dallas temp ds18b20

https://community.home-assistant.io/t/how-to-help-us-help-you-or-how-to-ask-a-good-question/114371#oneone-format-it-properly-16

Additionally

What error, exactly?

My feeling is that you have to use a physical GPIO of the ESP board for your 1-wire bus.