DOC: update conf.py to use new numpy doc url

[codeloop]

• closes DOC: Update numpy website url #33953
• tests added / passed
• passes black pandas
• passes git diff upstream/master -u -- "*.py" | flake8 --diff
• whatsnew entry

[datapythonista]

Thanks @codeloop, did you build the docs locally and checked that the link is working all right? I guess the intersphinx file is available at the new URL, but we need to make sure before merging this. Thanks!

[codeloop]

@datapythonista , I'm building the docs, following the steps from here Contributing to the documentation, will update after build is complete & tested locally.

[codeloop]

successfully built documentation locally using this commit, now the links point to numpy URL.
For eg: In the pandas docs at https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.Series.argsort.html
earlier it was referencing to : https://docs.scipy.org/doc/numpy/reference/generated/numpy.ndarray.argsort.html#numpy.ndarray.argsort
After this commit & build it references to : https://numpy.org/doc/stable/reference/generated/numpy.ndarray.argsort.html#numpy.ndarray.argsort

Looks good to me.

[datapythonista]

Great, thanks @codeloop, lgtm

[datapythonista]

@jorisvandenbossche may be you want to have a look

[jorisvandenbossche]

Perfect, thanks!

[simonjayhawkins]

@meeseeksdev backport to 1.0.x