Update telemetry Opt-out for 6.1

[TravisEz13]

Issue Details

you can now opt-out of telemetry by setting POWERSHELL_TELEMETRY_OPTOUT to yes
https://github.com/PowerShell/PowerShell/pull/6063/files#diff-187b8dbd25c60f08c04f26576d85249aR57

Version(s) of document impacted

• Impacts 6.1 document
• Impacts 6 document
• Impacts 5.1 document
• Impacts 5.0 document
• Impacts 4.0 document
• Impacts 3.0 document

Reason(s) for not selecting all version of documents

• The documented feature was introduced in selected version of PowerShell
• This issue only shows up in selected version of the document

[alexandair]

@sdwheeler
Please, close it. It's fixed by #2111.