Update changelog

Author: bartTC

CHANGES.rst

@@ -6,13 +6,15 @@ WIP
 ===
 
 - Added ``GappedCircleModuleDrawer`` (PIL) to render QR code modules as non-contiguous circles. (BenwestGate in `#373`_)
+- Improved test coveraged (akx in `#315`_)
 - Migrate pyproject.toml to PEP 621-compliant [project] metadata format. (hroncok in `#399`_)
 - Allow execution as a Python module. (stefansjs in `#400`_)
 
   ::
 
     python -m qrcode --output qrcode.png "hello world"
 
+.. _#315: https://github.com/lincolnloop/python-qrcode/pull/315
 .. _#373: https://github.com/lincolnloop/python-qrcode/pull/373
 .. _#399: https://github.com/lincolnloop/python-qrcode/pull/399
 .. _#400: https://github.com/lincolnloop/python-qrcode/pull/400