Fix icon url to render on nuget.org

Author: adityapatwardhan

build.psm1

@@ -521,7 +521,7 @@ function Start-BuildPowerShellNativePackage
         <requireLicenseAcceptance>true</requireLicenseAcceptance>
         <description>Native binaries for PowerShell Core</description>
             <projectUrl>https://github.com/PowerShell/PowerShell</projectUrl>
-            <iconUrl>https://github.com/PowerShell/PowerShell/blob/master/assets/Powershell_black_64.png</iconUrl>
+            <iconUrl>https://github.com/PowerShell/PowerShell/blob/master/assets/Powershell_black_64.png?raw=true</iconUrl>
             <licenseUrl>https://github.com/PowerShell/PowerShell/blob/master/LICENSE.txt</licenseUrl>
             <tags>PowerShell</tags>
             <language>en-US</language>