[2.0.x] Fixed #29334 -- Updated pypi.python.org URLs to pypi.org.

Backport of 64b74804c5 from master

docs/internals/contributing/writing-code/coding-style.txt

@@ -332,4 +332,4 @@ For details about the JavaScript code style used by Django, see
 :doc:`javascript`.
 
 .. _editorconfig: http://editorconfig.org/
-.. _flake8: https://pypi.python.org/pypi/flake8
+.. _flake8: https://pypi.org/project/flake8/

docs/internals/contributing/writing-code/unit-tests.txt

@@ -258,20 +258,20 @@ and install the Geospatial libraries</ref/contrib/gis/install/index>`.
 Each of these dependencies is optional. If you're missing any of them, the
 associated tests will be skipped.
 
-.. _argon2-cffi: https://pypi.python.org/pypi/argon2_cffi
-.. _bcrypt: https://pypi.python.org/pypi/bcrypt
-.. _docutils: https://pypi.python.org/pypi/docutils
-.. _geoip2: https://pypi.python.org/pypi/geoip2
-.. _jinja2: https://pypi.python.org/pypi/jinja2
-.. _numpy: https://pypi.python.org/pypi/numpy
-.. _Pillow: https://pypi.python.org/pypi/Pillow/
+.. _argon2-cffi: https://pypi.org/project/argon2_cffi/
+.. _bcrypt: https://pypi.org/project/bcrypt/
+.. _docutils: https://pypi.org/project/docutils/
+.. _geoip2: https://pypi.org/project/geoip2/
+.. _jinja2: https://pypi.org/project/jinja2/
+.. _numpy: https://pypi.org/project/numpy/
+.. _Pillow: https://pypi.org/project/Pillow/
 .. _PyYAML: https://pyyaml.org/wiki/PyYAML
-.. _pytz: https://pypi.python.org/pypi/pytz/
-.. _setuptools: https://pypi.python.org/pypi/setuptools/
+.. _pytz: https://pypi.org/project/pytz/
+.. _setuptools: https://pypi.org/project/setuptools/
 .. _memcached: https://memcached.org/
 .. _gettext: https://www.gnu.org/software/gettext/manual/gettext.html
-.. _selenium: https://pypi.python.org/pypi/selenium
-.. _sqlparse: https://pypi.python.org/pypi/sqlparse
+.. _selenium: https://pypi.org/project/selenium/
+.. _sqlparse: https://pypi.org/project/sqlparse/
 .. _pip requirements files: https://pip.pypa.io/en/latest/user_guide/#requirements-files
 
 Code coverage

docs/internals/contributing/writing-documentation.txt

@@ -424,11 +424,11 @@ Spelling check
 Before you commit your docs, it's a good idea to run the spelling checker.
 You'll need to install a couple packages first:
 
-* `pyenchant <https://pypi.python.org/pypi/pyenchant/>`_ (which requires
+* `pyenchant <https://pypi.org/project/pyenchant/>`_ (which requires
   `enchant <https://www.abisource.com/projects/enchant/>`_)
 
 * `sphinxcontrib-spelling
-  <https://pypi.python.org/pypi/sphinxcontrib-spelling/>`_
+  <https://pypi.org/project/sphinxcontrib-spelling/>`_
 
 Then from the ``docs`` directory, run ``make spelling``. Wrong words (if any)
 along with the file and line number where they occur will be saved to