Use Azure-Functions-compatible Microsoft.Extensions.Logging (#897)

* modify version of Microsoft.Extensions.Logging to be 6.0.0 when building net6.0 target

* update FASTER.core.nuspec also

Author: sebastianburckhardt

cs/src/core/FASTER.core.csproj

@@ -58,6 +58,11 @@
 		<PackageReference Include="Microsoft.Extensions.Logging" Version="3.1.26" />
 	  </ItemGroup>
 	</When>
+    <When Condition="'$(TargetFramework)' == 'net6.0'">
+      <ItemGroup>
+        <PackageReference Include="Microsoft.Extensions.Logging" Version="6.0.0" />
+      </ItemGroup>
+    </When>
     <Otherwise>
 	  <ItemGroup>
 		<PackageReference Include="Microsoft.Extensions.Logging" Version="7.0.0" />

cs/src/core/FASTER.core.nuspec

@@ -32,7 +32,7 @@
       <group targetFramework="net6.0">
         <dependency id="System.Runtime.CompilerServices.Unsafe" version="6.0.0" />
         <dependency id="System.Interactive.Async" version="6.0.1" />
-		<dependency id="Microsoft.Extensions.Logging" version="7.0.0" />
+		<dependency id="Microsoft.Extensions.Logging" version="6.0.0" />
 	  </group>
       <group targetFramework="net7.0">
         <dependency id="System.Runtime.CompilerServices.Unsafe" version="6.0.0" />