[changelog] set release date
MODIFY
CHANGELOG.md
CHANGELOG.md
Changes
=======
-# 3.4.0 / Unreleased
+# 3.4.0 / 2019-11-11
* [FEATURE] Blacklist installation of 6.14.0 and 6.14.1. See [#652][] [@truthbk][]
* [FEATURE] Run fix + sanity check script before agent uninstalls. See [#652][] [@truthbk][]

[changelog] set release date