dezdez

It was missing the last character

Update install.md Windows PowerShell installation example is actually two commands.

2

Removed erroneous backtick character. This is two separate PowerShell commands. Closes # _Describe your proposed changes here._ - [x] Signed the [InfluxData CLA](https://www.influxdata.com/legal/cla/) ([if necessary](https://github.com/influxdata/docs-v2/blob/master/CONTRIBUTING.md#sign-the-influxdata-cla)) - [x] Rebased/mergeable