DOCSP-8953: [BIC] Release notes for v2.13.4 (#249)

* DOCSP-8953: [BIC] Release notes for v2.13.4

Author: steveren

source/release-notes.txt

@@ -20,6 +20,19 @@ Release Notes for |bi|
 .. expect and we don't break the links on the downloads page.
 .. (DOCS-9670 for context)
 
+.. _bi-2-13-4:
+
+|bi| 2.13.4
+-----------
+
+*Released February 12, 2020*
+
+Bug Fixes
+~~~~~~~~~
+
+- Fixes bug in mapping that did not deep copy pipelines during table
+  post-processing, leading to invalid SQL schemas.
+
 .. _bi-2-13-3:
 
 |bi| 2.13.3