Update README.md for PS7 compatibility.

Yes, it works great with PowerShell 7.0.0.

README.md

@@ -4,7 +4,7 @@ Office365DnsChecker will check one or more domains, to make sure that their curr
 <img src="https://raw.githubusercontent.com/rhymeswithmogul/Office365DnsChecker/master/Logo/Office365DnsChecker.png" alt="Office365DnsChecker logo" width="432" height="300" style="margin:0 auto">
 
 ## System Requirements
-This module requires Windows PowerShell 5.1, PowerShell Core 6, or PowerShell 7 (tested up to 7.0.0-preview5).
+This module requires Windows PowerShell 5.1 or greater.  It works great on PoewrShell Core.
 
 Additionally, Linux users will need to install the app `dig` (part of [`bind-utils`](https://github.com/tigeli/bind-utils)).  It is installed by default on macOS (at least in High Sierra).
 
@@ -70,4 +70,4 @@ $error[0].ErrorDetails.RecommendedAction
 
 While the included one- or two-sentence tips may be useful for giving Office 365 administrators some idea on how to fix any DNS problems, you should still consult the [Microsoft 365 Admin Center](https://admin.microsoft.com)'s Domains page, which will tell you all but exactly how to fix your DNS records in common scenarios.
 
-In some cases, DNS records may intentionally be incorrect -- for example, if you have a third-party spam filter sitting in front of Exchange Online that requires custom MX records; or, if you have an on-premises Skype for Business Server that requires your Teams-/Skype-related DNS CNAME records to be incorrect intentionally.  Please consult your IT department or your local <abbr title="Microsoft Certified Solution Expert">MCSE</abbr> to make sure that following this module's generic advice won't interrupt your company's operations.
+In some cases, DNS records may intentionally be incorrect -- for example, if you have a third-party spam filter sitting in front of Exchange Online that requires custom MX records; or, if you have an on-premises Skype for Business Server that requires your Teams-/Skype-related DNS CNAME records to be incorrect intentionally.  Please consult your IT department or your local <abbr title="Microsoft Certified Solution Expert">MCSE</abbr> to make sure that following this module's generic advice won't interrupt your company's operations.