Missing completion for preview versions

[Neme12]

Installed product versions

• Visual Studio: 16.4.0 Preview 2.0
• This extension: 1.3.1

Description

There is no completion for some preview version numbers of packages.

Steps to recreate

1. Start with this .csproj file:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>netcoreapp3.0</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="3.0.0" />
  </ItemGroup>

</Project>

2. Delete "3.0.0" and start typing a new version number.

Current behavior

The highest version offered is "3.0.0".

Expected behavior

I should also be offered "3.1.0-preview1.19506.2" and "3.1.0-preview2.19525.5" because they've been released already:
https://www.nuget.org/packages/Microsoft.EntityFrameworkCore.SqlServer