Update dotnet-etcd package to version 8.1.0 and add Proto.Cluster.Etc…

[tgroves-tgiapps]

…d project to solution to have nuget package published.

Description

Added the Proto.Cluster.Etcd project to the solution so that a nuget package is published and users will not have to add the provider as a project reference.

Purpose

This pull request is a:

• Upgrade etcd-dotnet library
• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

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