devops: set up docker test and publish for NET 8 and 9

[timbze]

Here is a PR to do docker build testing and publishing for both NET 8 and 9. I have not tested this as it's not trivial to test without setting up docker hub, secrets, etc.

Fixes #3075

• 9.0-jammy docker image does not exist. I could just change the 2 .sh scripts to exit gracefully when trying to run for that configuration.

[timbze]

@microsoft-github-policy-service agree

[timbze]

Need to remove

[timbze]

The jammy 8.0 test that failed (only 1) is a timeout and I guess not related to this PR

[mxschmitt]

Thank you for your contribution! We recommend installing it manually on top of our existing image see the docs here since this is a STS version.

[timbze]

@mxschmitt thank you, I didn't think of it working that simple. Should work for me then.

[Kralizek]

Thank you for your contribution! We recommend installing it manually on top of our existing image see the docs here since this is a STS version.

A release being STS or LTS shouldn't be a deciding factor imho.

Especially since Microsoft is trying to push the idea that STS and LTS are qualitative equivalent.

[petrikero]

Just a heads up to others using the recommended approach, the proposed URL https://dot.net/v1/dotnet-install.sh has been quite unreliable and often has downtime. The direct GitHub URL https://raw.githubusercontent.com/dotnet/install-scripts/refs/heads/main/src/dotnet-install.sh is much more reliable.

Another downside of using the install script in your docker files is that it doesn't cache well in CI systems. For example, on GitHub, it takes around 8 seconds. An official .NET 9 image of Playwright would fix this.