Recommended changes resulting from automated audit

We performed an automated audit of your Cake addin and found that it does not follow all the best practices.

We encourage you to make the following modifications:

- [ ] You are currently referencing Cake.Core 0.17.0. Please upgrade to 0.28.0
- [ ] Your addin should target netstandard2.0. Please note that there is no need to multi-target, netstandard2.0 is sufficient.
- [ ] The nuget package for your addin should use the cake-contrib icon. Specifically, your addin's `.csproj` should have a line like this: `https://cdn.rawgit.com/cake-contrib/graphics/a5cf0f881c390650144b2243ae551d5b9f836196/png/cake-contrib-medium.png`.

Apologies if this is already being worked on, or if there are existing open issues, this issue was created based on what is currently published for this package on NuGet.org and in the project on github.

Inspect the addin's .csproj and NuGet package settings first, then verify the Cake.Core reference, target framework, and package icon metadata against the three checklist items. Restore and build the project, and confirm the resulting package contains the requested dependency, netstandard2.0 target, and Cake-Contrib icon URL.

Written by the indexing model from the issue text.