Remove System.Diagnostics.DiagnosticSource dependency from net 6+

[thompson-tomo]

Is your feature request related to a problem? Please describe.
I want to minimise dependencies in my project by utilising framework dependencies wherever possible

Describe the solution you'd like
I want the package to not have an explicit dependency on System.Diagnostics.DiagnosticSource on net 6+.

Describe alternatives you've considered
Accept the additional dependency

Additional context
n/a

[andrueastman]

Thanks for raising this @thompson-tomo

Would you be willing to submit a PR similar to #219 for this?

[thompson-tomo]

@andrueastman sure I will go through submitting PR's in the coming days.

[thompson-tomo]

Submitted as #220