Update CHANGELOG with 0.4.0/0.5.0 (#633)

Author: carlosalberto

CHANGELOG.md

@@ -7,7 +7,42 @@ the release.
 
 ## Unreleased
 
+## v0.5.0 (06-02-2020)
+
+- Define Log Data Model.
 - Remove SpanId from Sampler input.
+- Clarify what it will mean for a vendor to "support OpenTelemetry".
+- Clarify Tracers should reference an InstrumentationLibrary rather than a Resource.
+- Replace ALWAYS_PARENT sampler with a composite ParentOrElse sampler.
+- Incorporate old content on metrics calling conventions, label sets.
+- Update api-metrics-user.md and api-metrics-meter.md with the latest metrics API.
+- Normalize Instrumentation term for instrumentations.
+- Change w3c correlation context to custom header.
+
+## v0.4.0 (05-12-2020)
+
+- [OTEP-83](https://github.com/open-telemetry/oteps/blob/master/text/0083-component.md) Introduce the notion of InstrumentationLibrary.
+- [OTEP-88](https://github.com/open-telemetry/oteps/blob/master/text/metrics/0088-metric-instrument-optional-refinements.md) Metrics API instrument foundation.
+- [OTEP-91](https://github.com/open-telemetry/oteps/blob/master/text/logs/0091-logs-vocabulary.md) Logs vocabulary.
+- [OTEP-92](https://github.com/open-telemetry/oteps/blob/master/text/logs/0092-logs-vision.md) Logs Vision.
+- [OTEP-90](https://github.com/open-telemetry/oteps/blob/master/text/metrics/0090-remove-labelset-from-metrics-api.md) Remove LabelSet from the metrics API.
+- [OTEP-98](https://github.com/open-telemetry/oteps/blob/master/text/metrics/0098-metric-instruments-explained.md) Explain the metric instruments.
+- [OTEP-99](https://github.com/open-telemetry/oteps/blob/master/text/0099-otlp-http.md) OTLP/HTTP: HTTP Transport Extension for OTLP.
+- Define handling of null and empty attribute values.
+- Rename Setter.put to Setter.set
+- Add glossary for typically misused terms.
+- Clarify that resources are immutable.
+- Clarify that SpanContext.IsRemote is false on remote children.
+- Move specifications into sub-directories per signal.
+- Remove references to obsolete `peer.*` attributes.
+- Span semantic conventions for for messaging systems.
+- Span semantic conventions for function as a service.
+- Remove the handling of retries from trace exporters.
+- Remove Metrics' default keys.
+- Add some clarifying language to the semantics of metric instrument naming.
+- Allow injectors and extractors to be separate interfaces.
+- Add an explanation on why Context Restore operation is needed.
+- Document special Zipkin conversion cases.
 
 ## v0.3.0 (02-21-2020)