Update README.rst

Author: Willem Jan Faber

README.rst

@@ -15,7 +15,7 @@
 .. _SRU: http://www.loc.gov/standards/sru/
 .. _Travis: https://travis-ci.org/KBNLresearch/KB-python-API
 .. _CC-BY-NC-ND: https://creativecommons.org/licenses/by-nc-nd/2.0/
-.. _pypi: https://pypi.python.org/pypi/kb/
+.. _Pypi: https://pypi.python.org/pypi/kb/
 
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 KB python API: Access to National Library of the Netherlands datasets