Cleanup embed of nuget deps for the targets

[baronfel]

Is your feature request related to a problem? Please describe.

https://github.com/ionide/KeepAChangelog/blob/main/src/Ionide.KeepAChangelog.Tasks/Ionide.KeepAChangelog.Tasks.fsproj#L29-L37

• [x] explicitly specify the dlls expected so that we get errors if they are not found
• [x] remove the PDBs, they don't seem to be used for exception line numbers