update 20190831-newfeature.md

[JLKwong]

Problem

This tutorial blog asks you to name the mock feature temperature, but there is a real command called temperature. If someone approves the PR from this practice, they could accidentally replace create a duplicate of the real temperature command.

Steps to reproduce the problem

If you follow the New Feature blog, you will find yourself either creating a duplicate temperature command or replace the original temperature command.

Screenshots

Proposed solution

Replace all names of the mock function from temperature to faketemp.

[Mia-XXXX]

The issue title is confusing as it duplicated with your other issue. I suggest to have a better title to reflect the file and issue