FlubuCore: Unhandled exception. FlubuCore.Scripting.ScriptLoaderExcetpion

Describe the bug Getting error when running command flubu on root directory with a .flubu file

To Reproduce Steps to reproduce the behavior:

1. Using this version of the library ‘Flubu v.6.1.1.0’
2. Run this code

public class BuildScript : DefaultBuildScript
{
    [SolutionFileName]
    public string SolutionFileName { get; set; } = "ConsoleApp3.sln";

    protected override void ConfigureTargets(ITaskContext context)
    {
        context.LogInfo("started");
        var compile = context.CreateTarget("compile")
            .SetDescription("Compiles the solution.")
            .AddCoreTask(x => x.Build());

        var clean = context.CreateTarget("Clean")
            .SetDescription("Cleans the output of all projects in the solution.")
            .DependsOn(compile)
            .AddCoreTask(x => x.Clean());

        var restore = context.CreateTarget("Restore")
            .SetDescription("Restores the dependencies and tools of all projects in the solution.")
            .DependsOn(clean)
            .AddCoreTask(x => x.Restore());

        context.CreateTarget("Default")
            .SetDescription("Runs all targets.")
            .SetAsDefault()
            .DependsOn(restore);
    }
}

.flubu file BuildScript/BuildScript.csproj 3. With these arguments compile 4. See error

Flubu v.6.1.1.0
using the build script file path from .flubu file. 'BuildScript/BuildScript.csproj'.
ScriptError:CS1525: Invalid expression term '<'
ScriptError:CS1525: Invalid expression term '<'
ScriptError:CS1525: Invalid expression term '/'
ScriptError:CS1525: Invalid expression term '<'
ScriptError:CS1525: Invalid expression term '<'
ScriptError:CS1002: ; expected
ScriptError:CS1002: ; expected
ScriptError:CS1525: Invalid expression term '>'
ScriptError:CS1525: Invalid expression term '<'
ScriptError:CS1525: Invalid expression term '/'
ScriptError:CS1525: Invalid expression term '<'
ScriptError:CS1525: Invalid expression term '<'
ScriptError:CS1002: ; expected
ScriptError:CS1002: ; expected
ScriptError:CS1525: Invalid expression term '>'
ScriptError:CS1525: Invalid expression term '<'
ScriptError:CS1525: Invalid expression term '/'
ScriptError:CS1525: Invalid expression term '<'
ScriptError:CS1525: Invalid expression term '/'
ScriptError:CS1733: Expected expression
ScriptError:CS1002: ; expected
ScriptError:CS8805: Program using top-level statements must be an executable.
ScriptError:CS0103: The name 'Project' does not exist in the current context
ScriptError:CS0103: The name 'Sdk' does not exist in the current context
ScriptError:CS0103: The name 'PropertyGroup' does not exist in the current context
ScriptError:CS0103: The name 'TargetFramework' does not exist in the current context
ScriptError:CS0103: The name 'netcoreapp3' does not exist in the current context
ScriptError:CS0103: The name 'TargetFramework' does not exist in the current context
ScriptError:CS0103: The name 'PropertyGroup' does not exist in the current context
ScriptError:CS0103: The name 'ItemGroup' does not exist in the current context
ScriptError:CS0103: The name 'PackageReference' does not exist in the current context
ScriptError:CS0103: The name 'Include' does not exist in the current context
ScriptError:CS0103: The name 'Version' does not exist in the current context
ScriptError:CS0103: The name 'ItemGroup' does not exist in the current context
ScriptError:CS0103: The name 'ItemGroup' does not exist in the current context
ScriptError:CS0103: The name 'DotNetCliToolReference' does not exist in the current context
ScriptError:CS0103: The name 'Include' does not exist in the current context
ScriptError:CS0103: The name 'Version' does not exist in the current context
ScriptError:CS0103: The name 'ItemGroup' does not exist in the current context
ScriptError:CS0103: The name 'Project' does not exist in the current context
Unhandled exception. FlubuCore.Scripting.ScriptLoaderExcetpion: Csharp source code file: BuildScript/BuildScript.csproj has some compilation errors! If your script doesn't have compilation errors in VS or VSCode script probably doesn't include .cs file. To resolve this issue you should see build script fundamentals section 'Adding other .cs files to script' for more details: https://flubucore.dotnetcore.xyz/referencing-external-assemblies/#adding-other-cs-files-to-script
   at FlubuCore.Scripting.ScriptLoader.CompileBuildScript(String buildScriptAssemblyPath, String buildScriptFilePath, IEnumerable`1 references, String code) in c:\jenkins\workspace\FlubuCore\src\FlubuCore\Scripting\ScriptLoader.cs:line 250
   at FlubuCore.Scripting.ScriptLoader.FindAndCreateBuildScriptInstanceAsync(CommandArguments args) in c:\jenkins\workspace\FlubuCore\src\FlubuCore\Scripting\ScriptLoader.cs:line 124
   at FlubuCore.Scripting.ScriptProvider.GetBuildScriptAsync(CommandArguments commandArguments, Boolean forceReload) in c:\jenkins\workspace\FlubuCore\src\FlubuCore\Scripting\ScriptProvider.cs:line 26
   at DotNet.Cli.Flubu.Program.FlubuStartup(String[] args) in c:\jenkins\workspace\FlubuCore\src\dotnet-flubu\Program.cs:line 84
   at DotNet.Cli.Flubu.Program.Main(String[] args) in c:\jenkins\workspace\FlubuCore\src\dotnet-flubu\Program.cs:line 36
   at FlubuCore.Tool.Program.Main(String[] args) in c:\jenkins\workspace\FlubuCore\src\FlubuCore.Tool\Program.cs:line 9
   at FlubuCore.Tool.Program.<Main>(String[] args)