Add `DOTNET_NOLOGO` env var

[dhirschfeld]

Solution to issue cannot be found in the documentation.

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Issue

Should hopefully get rid of the welcome messages:

Welcome to .NET 6.0!
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SDK Version: 6.0.301

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Installed an ASP.NET Core HTTPS development certificate.
To trust the certificate run 'dotnet dev-certs https --trust' (Windows and macOS only).
Learn about HTTPS: https://aka.ms/dotnet-https
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Write your first app: https://aka.ms/dotnet-hello-world
Find out what's new: https://aka.ms/dotnet-whats-new
Explore documentation: https://aka.ms/dotnet-docs
Report issues and find source on GitHub: https://github.com/dotnet/core
Use 'dotnet --help' to see available commands or visit: https://aka.ms/dotnet-cli
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• https://docs.microsoft.com/en-us/dotnet/core/tools/dotnet-environment-variables#dotnet_nologo

Installed packages

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Environment info

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