Maintain current build solution (#1268)

* Add .NET 8.0 to current build project.
Add dependency **Microsoft.Bcl.AsyncInterfaces** for net462 and netstandard2.0 for current nuget spec

* Remove last new line

* Tabify

Author: scott-xu

build/build.proj

@@ -37,6 +37,10 @@
 			<OutputDirectory>Renci.SshNet\bin\$(Configuration)\net7.0</OutputDirectory>
 			<Moniker>net7.0</Moniker>
 		</TargetFrameworkModern>
+		<TargetFrameworkModern Include=".NET 8.0">
+			<OutputDirectory>Renci.SshNet\bin\$(Configuration)\net8.0</OutputDirectory>
+			<Moniker>net8.0</Moniker>
+		</TargetFrameworkModern>
 	</ItemGroup>
 
 	<Target Name="CleanModern" DependsOnTargets="CleanSolutionModern">

build/nuget/SSH.NET.nuspec

@@ -16,8 +16,11 @@
         <language>en-US</language>
         <tags>ssh scp sftp</tags>
         <dependencies>
-          <group targetFramework="net462" />
+          <group targetFramework="net462">
+            <dependency id="Microsoft.Bcl.AsyncInterfaces" version="[7.0.0]" />
+          </group>
           <group targetFramework="netstandard2.0">
+            <dependency id="Microsoft.Bcl.AsyncInterfaces" version="[7.0.0]" />
             <dependency id="SshNet.Security.Cryptography" version="[1.3.0]" />
           </group>          
           <group targetFramework="netstandard2.1">