Update meltingpot.md #155

	name: build
	on: [pull_request, push]

	permissions:
	contents: read # to fetch code (actions/checkout)

	jobs:
	optional-test-meltingpot:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v2

	# Melting Pot
	- run: \|
	docker build -f bin/meltingpot.Dockerfile \
	--build-arg PYTHON_VERSION='3.9' \
	--tag shimmy-meltingpot-docker .
	- name: Run meltingpot tests
	run: docker run shimmy-meltingpot-docker pytest tests/test_meltingpot.py

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