Update Poetry install script to install-poetry.py (#2965)

docs/contribute.rst

@@ -21,10 +21,10 @@ another, so you can use different packages (and package versions) for each.
 
 Please note that Python 3.6+ is required for Pelican development.
 
-*(Optional)* If you prefer to install Poetry once for use with multiple projects,
+*(Optional)* If you prefer to `install Poetry <https://python-poetry.org/docs/master/#installation>`_ once for use with multiple projects,
 you can install it via::
 
-    curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py | python -
+    curl -sSL https://install.python-poetry.org | python3 -
 
 Point your web browser to the `Pelican repository`_ and tap the **Fork** button
 at top-right. Then clone the source for your fork and add the upstream project
@@ -51,7 +51,7 @@ Install the needed dependencies and set up the project::
 Your local environment should now be ready to go!
 
 .. _Pip: https://pip.pypa.io/
-.. _Poetry: https://poetry.eustace.io/docs/#installation
+.. _Poetry: https://python-poetry.org/
 .. _Pelican repository: https://github.com/getpelican/pelican
 
 Development