rfc: upgrade projects to .NET 6

[vnbaaij]

💬 RFC

Propose to upgrade the projects to .NET 6.

🔦 Context

.NET 6 will be out in November, is going to be a Long Term Support (LTS) release and brings numerous improvements to Blazor. As this library is now only at a 0.3 version, it makes sense to upgrade to .NET 6 before doing a 1.0 release as .NET 6 will be out long before that. Also, .NET 6 is at RC1 stage now and comes with Go Live-support.

With moving to .NET 6 we can remove the custom FluentInputBase implementation and instead inherit from the standard ASP.NET Core InputBase and thereby rely on a robust and thoroughly tested implementation, current enhancements (use input components without EditContext) and future improvements (solving #58)
This won't be possible until .NET 7

As a final part of this change I propose to enable Nullability checks for the projects. With .NET 6 a larger part of the base classes (including ASP.NET Core) have this enabled now. Enabling this allows to get rid of a number of compile time warnings we are getting now.

[vnbaaij]

The work for this is done and can be seen at https://github.com/vnbaaij/fast-blazor/tree/net6. After giving people some to to react to this RFC, a PR will be created with these changes

[vnbaaij]

The PR is there now but the GitHub Actions Workflow 'ci-daily' is failing because it is targeting .NET 5. When the PR is merged the yml file needs to be updated to:

- name: Setup .NET SDK
      uses: actions/setup-dotnet@v1.8.1
      with:
        dotnet-version: 6.0.x
        include-prerelease: true 

[GurliGebis]

The PR is there now but the GitHub Actions Workflow 'ci-daily' is failing because it is targeting .NET 5. When the PR is merged the yml file needs to be updated to:

- name: Setup .NET SDK
      uses: actions/setup-dotnet@v1.8.1
      with:
        dotnet-version: 6.0.x
        include-prerelease: true 

Maybe I'm asking a stupid question, but wouldn't it be possible to update the yml file in your branch, and have it use that version when running the ci-daily workflow?

[vnbaaij]

I updated the yml file in my branch and enabled Workflows to run on my fork (it normaly dos not do that). The action is run succesfully on my branch now.

[EisenbergEffect]

Merged! Thanks @vnbaaij !