Fastparquet. adds fastparquet and the cramjam backend.

In progress (both build on my machine, untested so far)
from pytest_pyodide import run_in_pyodide


@run_in_pyodide(packages=["Jinja2"])
def test_jinja2(selenium):
    import jinja2

    template = jinja2.Template("Hello {{ name }}!")
    content = template.render(name="Zach")
    assert content == "Hello Zach!"

from pytest_pyodide import run_in_pyodide


@run_in_pyodide(packages=["Jinja2"])
def test_jinja2(selenium):
    import jinja2

    template = jinja2.Template("Hello {{ name }}!")
    content = template.render(name="Zach")
    assert content == "Hello Zach!"
