Update release/index.rst with 0.1.4 (#988)

Co-authored-by: Jay Chia <[email protected]@users.noreply.github.com>

Author: jaychia

docs/source/release_notes/index.rst

@@ -3,6 +3,7 @@ Release Notes
 
 .. toctree::
 
+    v0.1.4 <0.1.4>
     v0.1.3 <0.1.3>
     v0.1.2 <0.1.2>
     v0.1.1 <0.1.1>