standardize on Python 3.9 #119

	# 🏃‍♀️ Continuous Integration and Delivery: Branch Testing
	# ======================================================


	---

	name: 🔁 Branch integration testing


	# Driving Event
	# -------------
	#
	# What event starts this workflow: a push to any branch other than main

	on:
	push:
	branches:
	- '**'
	- '!main'


	# What to Do
	# ----------
	#
	# Test the software with tox

	jobs:
	branch-testing:
	name: 🪵 Branch Testing
	runs-on: ubuntu-latest
	if: github.actor != 'pdsen-ci'

	steps:
	-
	name: 💳 Checkout
	uses: actions/checkout@v3
	with:
	lfs: true
	fetch-depth: 0
	token: ${{secrets.ADMIN_GITHUB_TOKEN}}
	-
	name: Set up Python 3
	uses: actions/setup-python@v1
	with:
	python-version: '3.9'
	-
	name: 💵 Python Cache
	uses: actions/cache@v3
	with:
	path: ~/.cache/pip
	# The "key" used to indicate a set of cached files is the operating system runner
	# plus "py" for Python-specific builds, plus a hash of the wheels, plus "pds" because
	# we pds-prefix everything with "pds" in PDS! 😅
	key: pds-${{runner.os}}-py-${{hashFiles('*/.whl')}}
	# To restore a set of files, we only need to match a prefix of the saved key.
	restore-keys: pds-${{runner.os}}-py-
	-
	name: 🩺 Test Software
	run:
	pip install --editable '.[dev]'

	tox
	shell: bash

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