🧹 Housekeeping

• • Bumped Nuke.Common to 8.1.0 and updated build scripts.
• • Bumped required SDK to 8.0.401
• • Bumped Gitversion.Tool to 6.0.2
• • Bumped Roslynator.Analyzers to 4.12.5
• • Replaced NuGetVersion usage with SemVer variable as nuget package version number