<Project>
    <ItemGroup>
        <PackageReference Include="PackageOne" Version="$(Variable1)" />
        <PackageReference Include="$(variable2)" Version="6.0.0" />
        <PackageReference Include="" Version="2.4.1" />
        <PackageReference Include="package" Version="" />
        <PackageReference Include="PackageFour" Version="2.4.1" />
    </ItemGroup>
</Project>