Make dotnet-instrumentation-approvers codeowners of the operator dotnet instrumentation image

[swiatekm]

As of #4805, there's no need to manually update the operator container image as part of the release process of opentelemetry-dotnet-instrumentation. Nonetheless, operator maintainers would love to see dotnet instrumentation approvers approve the automated version update PRs.

This issue is a follow-up to @Kielek's comment here. In essence, what we'd like to do is make @open-telemetry/dotnet-instrumentation-approvers code owners of the following directory: https://github.com/open-telemetry/opentelemetry-operator/tree/main/autoinstrumentation/dotnet.

The operator has basic e2e tests verifying that an example dotnet app gets correctly instrumented and emits data. My primary expectation as an operator maintainer is that you'd let us know if there are any breaking changes in the new version worthy of calling out in the operator changelog. And, in the rare event that a PR is making changes to the Dockerfile, you'd be much better positioned to review it.

Let me know what you think.