Make non-shipping NuGet packages compliant

2020-10-21T00:20:39.6898014Z The package MsBuild.Engine.Corext 16.8.0-preview-20475-05 is not compliant.
2020-10-21T00:20:39.6898322Z There are 4 problems.
2020-10-21T00:20:39.6898690Z   - The package metadata defines 'msbtm@microsoft.com' as one of the authors which is not allowed by policy.
2020-10-21T00:20:39.6899114Z   - The package metadata contains a non-compliant copyright element.
2020-10-21T00:20:39.6899471Z   - The package metadata is missing required LicenseUrl.
2020-10-21T00:20:39.6899804Z   - The package metadata is missing required ProjectUrl.

2020-10-21T00:21:22.9608394Z The package VS.ExternalAPIs.MSBuild 16.8.0-preview-20475-05 is not compliant.
2020-10-21T00:21:22.9608865Z There are 4 problems.
2020-10-21T00:21:22.9609212Z   - The package metadata defines 'MSBuild' as one of the authors which is not allowed by policy.
2020-10-21T00:21:22.9609633Z   - The package metadata contains a non-compliant copyright element.
2020-10-21T00:21:22.9609992Z   - The package metadata is missing required LicenseUrl.
2020-10-21T00:21:22.9610306Z   - The package metadata is missing required ProjectUrl.

src/Package/DevDivPackage/VS.ExternalAPIs.MSBuild.nuspec

@@ -4,8 +4,11 @@
     <id>VS.ExternalAPIs.MSBuild</id>
     <summary>CoreXT package containing MSBuild binaries for the VS build.</summary>
     <description>CoreXT package containing MSBuild binaries for the VS build. Produced from the MSBuild $branchname$ branch.</description>
-    <authors>MSBuild</authors>
+    <authors>Microsoft</authors>
+    <copyright>© Microsoft Corporation. All rights reserved.</copyright>
+    <projectUrl>$projectUrl$</projectUrl>
     <version>0.0</version>
+    <license type="expression">$licenseExpression$</license>
     <dependencies>
       <group targetFramework=".NETFramework4.7.2" />
     </dependencies>
@@ -24,4 +27,4 @@
     <file src="Microsoft.Build.Framework.tlb" target="lib\net472" />
     <file src="Microsoft.Build.Tasks.Core.tlb" target="lib\net472" />
   </files>
-</package>
+</package>

src/Package/MSBuild.Engine.Corext/MsBuild.Engine.Corext.nuspec

@@ -4,8 +4,11 @@
     <id>MsBuild.Engine.Corext</id>
     <summary>Aggregate of MsBuild.Corext with the latest MSBuild team deliverables</summary>
     <description>Use this package to update your existing MsBuild.Corext package to the latest MSBuild binaries and core build files.</description>
+    <projectUrl>$projectUrl$</projectUrl>
+    <license type="expression">$licenseExpression$</license>
     <requireLicenseAcceptance>false</requireLicenseAcceptance>
-    <authors>msbtm@microsoft.com</authors>
+    <authors>Microsoft</authors>
+    <copyright>© Microsoft Corporation. All rights reserved.</copyright>
     <version>$version$</version>
   </metadata>