Update to v0.16.0 of go.opentelemetry.io/otel

[MrAlias]

Update Go minimum requirement to 1.14 to match the upstream go.opentelemetry.io/otel requirement.

go.opentelemetry.io/otel Release Notes:

Added

• Add the ReadOnlySpan and ReadWriteSpan interfaces to provide better control for accessing span data. (#1360)
• NewGRPCDriver function returns a ProtocolDriver that maintains a single gRPC connection to the collector. (#1369)
• Added documentation about the project's versioning policy. (#1388)
• Added NewSplitDriver for OTLP exporter that allows sending traces and metrics to different endpoints. (#1418)
• Added codeql worfklow to GitHub Actions (#1428)
• Added Gosec workflow to GitHub Actions (#1429)
• Add new HTTP driver for OTLP exporter in exporters/otlp/otlphttp. Currently it only supports the binary protobuf payloads. (#1420)

Changed

• Rename internal/testing to internal/internaltest. (#1449)
• Rename export.SpanData to export.SpanSnapshot and use it only for exporting spans. (#1360)
• Store the parent's full SpanContext rather than just its span ID in the span struct. (#1360)
• Improve span duration accuracy. (#1360)
• Migrated CI/CD from CircleCI to GitHub Actions (#1382)
• Remove duplicate checkout from GitHub Actions workflow (#1407)
• Metric array aggregator renamed exact to match its aggregation.Kind (#1412)
• Metric exact aggregator includes per-point timestamps (#1412)
• Metric stdout exporter uses MinMaxSumCount aggregator for ValueRecorder instruments (#1412)
• NewExporter from exporters/otlp now takes a ProtocolDriver as a parameter. (#1369)
• Many OTLP Exporter options became gRPC ProtocolDriver options. (#1369)
• Unify endpoint API that related to OTel exporter. (#1401)
• Optimize metric histogram aggregator to re-use its slice of buckets. (#1435)
• Metric aggregator Count() and histogram Bucket.Counts are consistently uint64. (1430)
• SamplingResult now passed a Tracestate from the parent SpanContext (#1432)
• Moved gRPC driver for OTLP exporter to exporters/otlp/otlpgrpc. (#1420)
• The TraceContext propagator now correctly propagates TraceState through the SpanContext. (#1447)
• Metric Push and Pull Controller components are combined into a single "basic" Controller:
  • WithExporter() and Start() to configure Push behavior
  • Start() is optional; use Collect() and ForEach() for Pull behavior
  • Start() and Stop() accept Context. (#1378)

Removed

• Remove errUninitializedSpan as its only usage is now obsolete. (#1360)
• Remove Metric export functionality related to quantiles and summary data points: this is not specified (#1412)
• Remove DDSketch metric aggregator; our intention is to re-introduce this as an option of the histogram aggregator after new OTLP histogram data types are released (#1412)

Fixed

• BatchSpanProcessor.Shutdown() will now shutdown underlying export.SpanExporter. (#1443)

fixes #47

[RichVanderwal]

Works!

[RichVanderwal]

We plan on merging and releasing this work early next week, along with Getting Started documentation.