envvar-based sampler configuration capability should not be mentioned as part of 1.8.0-beta.1 changelog

[julealgon]

The recently added feature, to be able to configure trace samplers using environment variables:

• [sdk-traces] Add support for OTEL_TRACES_SAMPLER and OTEL_TRACES_SAMPLER_ARG #5448

Was added to the changelog for the OpenTelemetry project as if it was part of the 1.8.0-beta.1 release:

opentelemetry-dotnet/src/OpenTelemetry/CHANGELOG.md

Lines 84 to 92 in af57de2

	* `TracerProvider`s can now have a sampler configured via the
	`OTEL_TRACES_SAMPLER` environment variable. The supported values are:
	`always_off`, `always_on`, `traceidratio`, `parentbased_always_on`,
	`parentbased_always_off`, and `parentbased_traceidratio`. The options
	`traceidratio` and `parentbased_traceidratio` may have the sampler probability
	configured via the `OTEL_TRACES_SAMPLER_ARG` environment variable.
	For details see: [OpenTelemetry Environment Variable
	Specification](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/configuration/sdk-environment-variables.md#general-sdk-configuration).
	([#5448](https://github.com/open-telemetry/opentelemetry-dotnet/pull/5448))

This is however incorrect: the feature was merged after v1.8.0-beta.1 had already released. This should've instead been added to the "Unreleased" section.

Note the dates:
Merge on March 19th

Release on March 14th:

This particular issue caused me to waste a couple hours yesterday testing the functionality. I had found the environment variables in the OTEL Spec documentation, searched for them in the repo, and found out "it was added as part of v1.8.0-beta.1". So I proceeded to upgrade the library on our project and try to make it work.

I'm aware this was not mentioned in the actual release notes however, but I didn't look at that until much later, and that's when I noticed the 'CHANGELOG.md' had more changes in it than the release notes and everything clicked for me.

This is more of a documentation change request so I felt it made sense to open an issue vs a discussion.

Related:

• Unintentional breaking changes? MethodAccessException when attempting to migrate from v1.7.0 to v1.8.0-beta.1 #5477

[Kielek]

@julealgon, could you please create PR and move the entry to unreleased section?

[Kielek]

Can be closed by #5483