Default dependencies refer to net5.0 framework

Description

Initializing a new F# project and using paket breaks the project.

Repro steps

Make sure that .net6 or .net7 are installed.

1. create a new project with dotnet new console -lang F#
2. install paket
3. add any dependency, e.g. dotnet paket add FSharp.Core
4. dotnet run

Expected behavior

We see the Hello from F#! output

Actual behavior

Unhandled exception. System.IO.FileNotFoundException: Could not load file or assembly 'FSharp.Core, Version=7.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.
File name: 'FSharp.Core, Version=7.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'

Known workarounds

Make sure that the .fsproj and paket.dependencies files agree on the framework.
For example use framework: auto-detect in the paket.dependencies file.

I would suggest changing the default template that is crated with paket init to auto-detect. This seems to me to be the easiest, and most beginner-friendly way.

I located, what I think, are the relevant lines of code. In the Environment.fs file at the very bottom

let init (directory : DirectoryInfo) =
        let sources = [PackageSources.DefaultNuGetV3Source]
        let additionalLines = [
            "storage: none"
            "framework: net5.0, netstandard2.0, netstandard2.1"
        ]
        initWithContent sources additionalLines directory

But maybe there is a good reason, which I don't know, for not using auto-detect as the default.

Start in Environment.fs at the init function and reproduce the failure with the listed dotnet and Paket commands. Check how paket init generates paket.dependencies, then confirm the default framework setting is compatible with the new project's target and that dotnet run produces the expected Hello from F#! output.