Release 1.21.0 (#3474)

May Release.

Author: carlosalberto

CHANGELOG.md

@@ -13,8 +13,38 @@ release.
 
 ### Metrics
 
+### Logs
+
+### Resource
+
+### Compatibility
+
+### OpenTelemetry Protocol
+
+### SDK Configuration
+
+### Telemetry Schemas
+
+### Common
+
+### Supplemenatary Guidelines
+
+## v1.21.0 (2023-05-09)
+
+### Context
+
+- No changes.
+
+### Traces
+
+- No changes.
+
+### Metrics
+
 - Add experimental histogram advice API.
   ([#3216](https://github.com/open-telemetry/opentelemetry-specification/pull/3216))
+- Recommended non-prefixed units for metric instrument semantic conventions.
+  ([#3312](https://github.com/open-telemetry/opentelemetry-specification/pull/3312))
 - Recommended cardinality limits to protect metrics pipelines against
   excessive data production from a single instrument.
   ([#2960](https://github.com/open-telemetry/opentelemetry-specification/pull/2960))
@@ -30,6 +60,8 @@ release.
   ([#3345](https://github.com/open-telemetry/opentelemetry-specification/pull/3354))
 - Drop logger include_trace_context parameter.
   ([#3397](https://github.com/open-telemetry/opentelemetry-specification/pull/3397))
+- Clarify how ObservedTimestamp field is set if unspecified
+  ([#3385](https://github.com/open-telemetry/opentelemetry-specification/pull/3385))
 - Mark logs bridge API / SDK as stable.
   ([#3376](https://github.com/open-telemetry/opentelemetry-specification/pull/3376))
 - Mark LogRecord Environment Variables as stable.
@@ -46,13 +78,13 @@ release.
 
 ### Compatibility
 
-### Supplemenatary Guidelines
-
-- Add guidance to use service-supported propagation formats as default for AWS SDK client calls.
-  ([#3212](https://github.com/open-telemetry/opentelemetry-specification/pull/3212))
+- Mark OpenCensus compatibility spec as stable
+  ([#3425](https://github.com/open-telemetry/opentelemetry-specification/pull/3425))
 
 ### OpenTelemetry Protocol
 
+- No changes.
+
 ### SDK Configuration
 
 - Lay initial groundwork for file configuration
@@ -65,11 +97,18 @@ release.
 
 ### Telemetry Schemas
 
+- No changes.
+
 ### Common
 
 - Add log entries to specification README.md contents.
   ([#3435](https://github.com/open-telemetry/opentelemetry-specification/pull/3435))
 
+### Supplemenatary Guidelines
+
+- Add guidance to use service-supported propagation formats as default for AWS SDK client calls.
+  ([#3212](https://github.com/open-telemetry/opentelemetry-specification/pull/3212))
+
 ## v1.20.0 (2023-04-07)
 
 ### Context
@@ -88,8 +127,6 @@ release.
 
 - Clarify that units should use UCUM case sensitive variant.
   ([#3306](https://github.com/open-telemetry/opentelemetry-specification/pull/3306))
-- Recommended non-prefixed units for metric instrument semantic conventions.
-  ([#3312](https://github.com/open-telemetry/opentelemetry-specification/pull/3312))
 - Remove No-Op instrument and Meter creation requirements.
   ([#3322](https://github.com/open-telemetry/opentelemetry-specification/pull/3322))
 - Fixed attributes requirement level in semantic conventions for hardware metrics
@@ -116,8 +153,6 @@ release.
 
 ### Semantic Conventions
 
-- Add k8s.cluster.uid semantic convention
-  ([#3267](https://github.com/open-telemetry/opentelemetry-specification/pull/3267))
 - Clarify that attribute requirement levels apply to the instrumentation library
   ([#3289](https://github.com/open-telemetry/opentelemetry-specification/pull/3289))
 - Fix grammatical number of metric units.