Update quickstart.rst
Remove redundant 'the'.
@@ -25,7 +25,7 @@ above, install with :code:`pip` command:
pip install bentoml
-When referring the the latest documentation instead of the stable release doc, it is
+When referring the latest documentation instead of the stable release doc, it is
required to install the preview release of BentoML:
.. code-block:: bash
