Add support for TEMPer1F_H1V1.5F

[urwen]

Firmware TEMPer1F_H1V1.5F (id 0c45:7402) seems to be using a different temperature sensor (SHT20). This change adds support for this sensor/firmware combination.

[urwen]

BTW, I have rebased all of your changes onto urwen/temper. There is one PR over there you should look at, because I think it's a one-line change to support another version: https://github.com/urwen/temper/pull/29

I want to thank you for forking temper and maintaining it for these past several years. I really appreciate it!!! I've put a note in my README.md to point to this repository, and I'll submit changes here if I add support for more devices.

[ccwienk]

@urwen : npb. however, I think "maintaining" is giving me too much credit. basically, I forked it once to add a fix I needed, and then I actually almost forgot about the fork 🙈

I think I just caused a conflict by admitting another pullrequest that proposed the same change :(

[ccwienk]

@urwen : I made you collaborator