fixes updgrade -> upgrade typo
very minor typo fixed in getting_started.rst
@@ -116,7 +116,7 @@ To update the repository, do::
If you have set the repository,
this command does ``git pull`` and ``git push``
-in addition to such brew's ``install``, ``clean``, ``update``, ``updgrade`` and removing packages
+in addition to such brew's ``install``, ``clean``, ``update``, ``upgrade`` and removing packages
described in online storages section above.
It is good if you have such a cron job like::
