Trivial: update pypi url to new url

Change-Id: I069ca4e8cfbd3d991c958e5383eee327c443402c

CHANGELOG.rst

@@ -112,6 +112,6 @@ Fixed
 ~~~~~
 
 * The support of `kubernetes python client
-  <https://pypi.python.org/pypi/kubernetes>`_ (which is used by Magnum plugins)
+  <https://pypi.org/project/kubernetes>`_ (which is used by Magnum plugins)
   is not limited by 3.0.0 max version. You can use more modern releases of that
   library.

doc/source/quick_start/tutorial/step_5_task_templates.rst

@@ -375,4 +375,4 @@ shared with others.
 
 .. references:
 
-.. _Jinja2: https://pypi.python.org/pypi/Jinja2
+.. _Jinja2: https://pypi.org/project/Jinja2

tests/ci/sync_requirements.py

@@ -84,7 +84,7 @@ class PYPIPackage(object):
             if self.package_name in _PYPI_CACHE:
                 self._pypi_info = _PYPI_CACHE[self.package_name]
             else:
-                resp = requests.get("https://pypi.python.org/pypi/%s/json" %
+                resp = requests.get("https://pypi.org/pypi/%s/json" %
                                     self.package_name)
                 if resp.status_code != 200:
                     print("An error occurred while checking '%s' package at "