release: Release 2 gems

[otelbot-ruby-contrib]

This pull request prepares new gem releases for the following gems:

• opentelemetry-instrumentation-rack 0.27.1 (was 0.27.0)
• opentelemetry-instrumentation-all 0.81.0 (was 0.80.0)

For each gem, this pull request modifies the gem version and provides an initial changelog entry based on conventional commit messages. You can edit these changes before merging, to release a different version or to alter the changelog text.

• To confirm this release, merge this pull request, ensuring the "release: pending" label is set. The release script will trigger automatically on merge.
• To abort this release, close this pull request without merging.

The generated changelog entries have been copied below:

---

opentelemetry-instrumentation-rack

v0.27.1 / 2025-09-16

• DOCS: Typo in Rack::Instrumentation usage example of middleware_args

---

opentelemetry-instrumentation-all

v0.81.0 / 2025-09-16

• ADDED: Anthropic initial instrumentation
• ADDED: Add anthropic instrumentation to instrumentation_all

[kaylareopelle]

EasyCLA permissions changes prevent me from editing the text of this PR. I'll make a new PR to update the text of the changelog to remove anthropic duplication and add a note about Net::HTTP's support of OTEL_SEMCONV_STABILITY_OPT_IN.

PR to update the permissions: https://github.com/open-telemetry/admin/pull/260

[github-actions]

All releases completed successfully.

Successfully released opentelemetry-instrumentation-rack 0.27.1

Successfully released opentelemetry-instrumentation-all 0.81.0