v0.10.0

Stable-channel republication of 1.1.0-beta.14. Depends on
dartastic_opentelemetry_api: ^0.10.0.

The minor bump from 0.9.8 carries three breaking spec-compliance
changes:

• Sampler decisions are honored end to end (#120–#123, #129): dropped
  spans reach no processor, RecordOnly no longer sets the W3C Sampled
  flag, and exporters receive only sampled spans. Adjust your sampler
  configuration if you relied on unsampled spans being exported.
• The default sampler is ParentBased(root: AlwaysOn) (#126): child
  spans now respect an unsampled parent. Pass
  sampler: const AlwaysOnSampler() to restore the old behavior.
• OTelEnv configuration functions return typed Dart Records instead
  of Map<String, dynamic> (config['endpoint'] as String? →
  config.endpoint).

Also notable: OTLP/gRPC exporters default to port 4317 per the OTLP spec
(#220), OTLP requests carry an identifying User-Agent (#228), empty
environment variables read as unset (#213), service.name precedence is
fixed (#103), browser.* resource attributes are populated on web (#190)
with browser.mobile as a boolean, and baggage values containing =
survive extraction (#199). Full detail in the 1.1.0-beta.14 entry.