update changelog (#600)

Author: alrex

CHANGELOG.md

@@ -7,9 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased](https://github.com/open-telemetry/opentelemetry-python/compare/v1.4.0-0.23b0...HEAD)
 
-## [1.4.0-0.23b0](https://github.com/open-telemetry/opentelemetry-python/releases/tag/v1.4.0-0.23b0) - 2021-07-19
-
-
+## [1.4.0-0.23b0](https://github.com/open-telemetry/opentelemetry-python/releases/tag/v1.4.0-0.23b0) - 2021-07-21
 
 ### Removed
 - Move `opentelemetry-instrumentation` to the core repo.