Integrate scikit-learn's `set_output` method into `TransactionEncoder` #353

	name: Unit tests

	on:
	push:
	branches: master
	pull_request:
	branches: master

	jobs:
	build-linux:
	runs-on: ubuntu-latest
	strategy:
	max-parallel: 5

	steps:
	- uses: actions/checkout@v2
	- name: Set up Python 3.9
	uses: actions/setup-python@v2
	with:
	python-version: 3.9
	- name: Add conda to system path
	run: \|
	# $CONDA is an environment variable pointing to the root of the miniconda directory
	echo $CONDA/bin >> $GITHUB_PATH
	- name: Install packages and test with pytest
	run: \|
	conda config --add channels conda-forge
	conda update conda -y -q
	conda env update --file environment.yml --name base
	pip install scikit-learn==1.1.3
	pip install pandas==1.3.5
	conda install tensorflow joblib pytest -y -q
	conda install imageio scikit-image -y -q
	conda install dlib -y -q
	pip install markdown
	pip install coverage
	pip install -e .
	python -c "import numpy; print('NumPy:', numpy.__version__)"
	python -c "import scipy; print('SciPy:', scipy.__version__)"
	python -c "import sklearn; print('Scikit-learn:', sklearn.__version__)"
	python -c "import pandas; print('Pandas:', pandas.__version__)"
	coverage run --source=mlxtend --branch -m pytest mlxtend
	coverage xml
	- name: Upload Coverage to Codecov
	uses: codecov/codecov-action@v2

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