Remove stray characters at end of tutorial

The `publish-pypi.md` file ends with the start of code block (https://github.com/pyOpenSci/python-package-guide/blob/01de29ee6f6a08f4d1bd433ad6ea1824788c1396/tutorials/publish-pypi.md?plain=1#L403) and this causes issues when rendering the page, as per the attached screenshot.

This is a tiny fix while working on the trusted publishing tutorial (#253).

Signed-off-by: Mihai Maruseac <mihaimaruseac@google.com>

Author: mihaimaruseac

tutorials/publish-pypi.md

@@ -394,10 +394,6 @@ Once you publish on PyPI, you can then easily add your package to the conda-forg
 
 You will learn how to do that in the next lesson.
 
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 ## Footnotes
 
 [^venv]: https://docs.python.org/3/library/venv.html
-```