upgrade System.Data.SqlClient version.

src/DotNetCore.CAP.SqlServer/DotNetCore.CAP.SqlServer.csproj

@@ -11,7 +11,8 @@
   <ItemGroup>
     <PackageReference Include="Dapper" Version="1.50.2" />
     <PackageReference Include="Microsoft.EntityFrameworkCore" Version="2.0.0" />
-    <PackageReference Include="Microsoft.EntityFrameworkCore.Relational" Version="2.0.0" /> 
+    <PackageReference Include="Microsoft.EntityFrameworkCore.Relational" Version="2.0.0" />
+    <PackageReference Include="System.Data.SqlClient" Version="4.4.0" /> 
   </ItemGroup>
 
   <ItemGroup>