release: Release 3 gems

[otelbot]

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

• opentelemetry-instrumentation-httpx 0.3.0 (was 0.2.1)
• opentelemetry-instrumentation-excon 0.24.0 (was 0.23.0)
• opentelemetry-instrumentation-faraday 0.28.0 (was 0.27.0)

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-httpx

v0.3.0 / 2025-08-12

• ADDED: HTTPX OTEL_SEMCONV_STABILITY_OPT_IN environment variable #1589

---

opentelemetry-instrumentation-excon

v0.24.0 / 2025-08-12

• ADDED: Add Excon OTEL_SEMCONV_STABILITY_OPT_IN environment variable #1569

---

opentelemetry-instrumentation-faraday

v0.28.0 / 2025-08-12

• ADDED: Add Faraday OTEL_SEMCONV_STABILITY_OPT_IN environment variable #1592

---

[otelbot]

Release job completed with errors.

Successfully released opentelemetry-instrumentation-http 0.25.1

Failed to release opentelemetry-instrumentation-httpx 0.3.0:
Command failed with exit code 1: ["gh", "api", "repos/open-telemetry/opentelemetry-ruby-contrib/releases", "--input", "-", "-H", "Accept: application/vnd.github.v3+json"]

Failed to release opentelemetry-instrumentation-excon 0.24.0:
Command failed with exit code 1: ["gh", "api", "repos/open-telemetry/opentelemetry-ruby-contrib/releases", "--input", "-", "-H", "Accept: application/vnd.github.v3+json"]

Failed to release opentelemetry-instrumentation-faraday 0.28.0:
Command failed with exit code 1: ["gh", "api", "repos/open-telemetry/opentelemetry-ruby-contrib/releases", "--input", "-", "-H", "Accept: application/vnd.github.v3+json"]

Successfully released opentelemetry-instrumentation-all 0.78.0