* Updating the repo to use Directory.Build.props/targets files
* Adding an InternalsVisibleTo for DynamicProxyGenAssembly2, PublicKeyToken=null
* Removing duplicate includes from the ImageSharp.csproj
* Updating the .gitattributes file to explicitly list the line endings
* Removing the ImageSharp.ruleset file, as the one from standards should be used instead
* Updating the package version management to use `PackageReference Update`