fixup! Build: Read nuget API key from file

Build server's repo clone is volatile, so moved API key file to
%UserProfile%\AppData\Roaming\NuGet\unitsnet.apikey.txt

Author: angularsen

Build/nuget-apikey-placeholder.txt

@@ -1,6 +1,6 @@
 $root="$PSScriptRoot\.."
 $nugetDir="$root\Artifacts\NuGet\"
-$apiKeyFile="nuget-apikey.txt"
+$apiKeyFile="$env:appdata\NuGet\unitsnet-apikey.txt"
 
 $apiKey = Get-Content $apiKeyFile
 Write-Host "Using API key: $apiKey"