Add changelog for 1.1.1

CHANGELOG-1.0.md

@@ -1,5 +1,5 @@
-CHANGELOG
-=========
+CHANGELOG for 1.0.x
+===================
 
 This changelog references the relevant changes done in minor version updates.
 

CHANGELOG-1.1.md

@@ -1,8 +1,18 @@
-CHANGELOG
-=========
+CHANGELOG for 1.1.x
+===================
 
 This changelog references the relevant changes done in minor version updates.
 
+1.1.1 (2017-06-30)
+------------------
+
+All issues and pull requests under this release may be found under the
+[1.1.1](https://github.com/alcaeus/mongo-php-adapter/issues?q=milestone%3A1.1.1)
+milestone.
+
+ * [#176](https://github.com/alcaeus/mongo-php-adapter/pull/176) fixes exception
+ codes in `MongoGridFSException` exceptions that occur during GridFS operations.
+
 1.1.0 (2017-05-13)
 ------------------