Bump release to v3.9.8.7

CHANGELOG.md

@@ -8,6 +8,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ### v3.9.x - [Unreleased]
 
+### v3.9.8.7 - 2019-08-31
+
 #### Changed
 
 - WordPress default permalinks structure from `/%year%/%monthnum%/%day%/%postname%/` -> `/%postname%/`
@@ -16,6 +18,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 - Error with `wo stack upgrade --nginx`
 - Install/update script version check
+- clamAV stack install
 
 ### v3.9.8.6 - 2019-08-30