Add changelog for 1.1.6

CHANGELOG-1.1.md

@@ -3,6 +3,21 @@ CHANGELOG for 1.1.x
 
 This changelog references the relevant changes done in minor version updates.
 
+1.1.6 (2019-02-08)
+------------------
+
+All issues and pull requests under this release may be found under the
+[1.1.6](https://github.com/alcaeus/mongo-php-adapter/issues?q=milestone%3A1.1.6)
+milestone.
+
+ * [#244](https://github.com/alcaeus/mongo-php-adapter/pull/244) fixes a null
+ acces when converting exceptions.
+ * [#236](https://github.com/alcaeus/mongo-php-adapter/pull/236) allows using
+ `0` as key in documents.
+ * [#234](https://github.com/alcaeus/mongo-php-adapter/pull/234) removes an
+ invalid attribute from phpunit.xml.
+
+
 1.1.5 (2018-03-05)
 -----------------