3.9.0 readiness

Updates the CHANGELOG.md to set the release date.

CHANGELOG.md

@@ -2,27 +2,24 @@
 
 All notable changes to this project will be documented in this file, in reverse chronological order by release.
 
-## 3.9.0 - TBD
+## 3.9.0 - 2021-09-18
 
-### Added
-
-- Nothing.
-
-### Changed
 
-- Nothing.
+-----
 
-### Deprecated
+### Release Notes for [3.9.0](https://github.com/laminas/laminas-servicemanager/milestone/17)
 
-- Nothing.
+Feature release (minor)
 
-### Removed
+### 3.9.0
 
-- Nothing.
+- Total issues resolved: **0**
+- Total pull requests resolved: **1**
+- Total contributors: **1**
 
-### Fixed
+#### Enhancement
 
-- Nothing.
+ - [98: Refined ServiceManager factory, delegator and configuration types, to allow for easier introspection of mis-configuration at type level](https://github.com/laminas/laminas-servicemanager/pull/98) thanks to @boesing
 
 ## 3.8.0 - 2021-09-14