Hide aws sdk package. (#981)

Author: DmitryLukyanov

src/MongoDB.Driver.Core/MongoDB.Driver.Core.csproj

@@ -19,7 +19,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="AWSSDK.SecurityToken" Version="3.7.100.14" />
+    <PackageReference Include="AWSSDK.SecurityToken" Version="3.7.100.14" PrivateAssets="All" />
     <PackageReference Include="DnsClient" Version="1.6.1" />
     <PackageReference Include="MongoDB.Libmongocrypt" Version="1.6.0" />
     <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="2.0.0" />

tests/MongoDB.Driver.Tests/MongoDB.Driver.Tests.csproj

@@ -31,6 +31,7 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.8.0" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.0" />
+    <PackageReference Include="AWSSDK.SecurityToken" Version="3.7.100.14" PrivateAssets="All" />
   </ItemGroup>
 
   <ItemGroup>