docs(opentelemetry-node): note the new upstream plan for the HTTP semconv migration (#769)

Author: trentm

packages/opentelemetry-node/README.md

@@ -31,7 +31,7 @@ EDOT Node.js is very similar to the `@opentelemetry/auto-instrumentations-node`
 - EDOT Node.js includes the additional, Elastic-authored [`@elastic/opentelemetry-instrumentation-openai`](../instrumentation-openai) instrumentation for the OpenAI Node.js client library.
 - EDOT Node.js, being a [distribution](https://opentelemetry.io/docs/concepts/distributions/) of the OpenTelemetry JS SDK, always adds the [`telemetry.distro.*`](https://opentelemetry.io/docs/specs/semconv/attributes-registry/telemetry/) resource attributes to identify itself.
 - EDOT Node.js [enables some metrics by default](https://github.com/elastic/elastic-otel-node/blob/main/packages/opentelemetry-node/docs/metrics.md) that are not included by `@opentelemetry/auto-instrumentations-node`: a subset of metrics from `@opentelemetry/host-metrics`.
-- EDOT Node.js defaults to [`OTEL_SEMCONV_STABILITY_OPT_IN=http`](https://opentelemetry.io/docs/specs/semconv/non-normative/http-migration/) such that telemetry from the `@opentelemetry/instrumentation-http` package will use stable HTTP semantic conventions by default. Upstream OpenTelemetry JS currently has a [PR](https://github.com/open-telemetry/opentelemetry-js/pull/5552) that will change to the same behavior soon.
+- EDOT Node.js defaults to [`OTEL_SEMCONV_STABILITY_OPT_IN=http`](https://opentelemetry.io/docs/specs/semconv/non-normative/http-migration/) such that telemetry from the `@opentelemetry/instrumentation-http` package will use stable HTTP semantic conventions by default. Upstream OpenTelemetry JS has [a tracking issue for the migration to newer HTTP semantic conventions](https://github.com/open-telemetry/opentelemetry-js/issues/5646) in its instrumentations.
 - EDOT Node.js [defaults to `OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE=delta`](https://elastic.github.io/opentelemetry/edot-sdks/nodejs/configuration.html#otel_exporter_otlp_metrics_temporality_preference-details), which differs from the upstream OpenTelemetry JS default of `cumulative`.
 - EDOT Node.js uses the more recent [import-in-the-middle `createAddHookMessageChannel` feature](https://github.com/nodejs/import-in-the-middle/blob/main/README.md#only-intercepting-hooked-modules) for improved ESM support. We hope to upstream support for this.
 - Internal [diagnostic logging](https://github.com/open-telemetry/opentelemetry-js/blob/main/experimental/packages/opentelemetry-sdk-node/README.md#configure-log-level-from-the-environment) from EDOT Node.js is in a custom JSON-log format, rather than the message-string-only format from OpenTelemetry JS. diag logging in (luggite) JSON format