build(.readthedocs.yaml): Updated Python version. #49

	# This workflow is purely to determine code coverage.
	# Since we really only need to run coverage once (not N times for every combination
	# in a test matrix), there is some duplication with the primary testing workflow.

	name: Code Coverage

	on: [push, pull_request]

	env:
	python-version: 3.9

	jobs:
	coverage:
	runs-on: ubuntu-latest
	steps:
	- name: Checkout
	uses: actions/checkout@v4
	with:
	ref: ${{ github.event.pull_request.head.sha }}
	- name: Set up Python ${{ env.python-version }}
	uses: actions/setup-python@v5
	with:
	python-version: ${{ env.python-version }}
	- name: Install dependencies
	run: \|
	python -m pip install --upgrade pip
	python -m pip install pytest
	python -m pip install pytest-cov
	python -m pip install multidict
	- name: Install pvl
	run: python -m pip install -e .
	- name: Test with pytest and generate coverage report
	run: pytest --cov=./pvl --cov-report=xml
	- name: Upload coverage to Codecov
	uses: codecov/codecov-action@v5
	with:
	fail_ci_if_error: true
	token: ${{ secrets.CODECOV_TOKEN }}

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