[r12.0] update workflows for release branches #808

	name: Open-CE XGBoost Build

	on:
	push:
	branches:
	- 'main' # matches the main branch
	- 'r*' # matches every release branch
	pull_request:
	branches:
	- 'main' # matches the main branch
	- 'r*' # matches every release branch

	jobs:
	build:

	runs-on: ubuntu-latest

	strategy:
	matrix:
	python-version: ["3.8", "3.9", "3.10"]

	steps:
	- uses: actions/checkout@v2
	- uses: conda-incubator/[email protected]
	with:
	auto-update-conda: false
	python-version: ${{ matrix.python-version }}
	- name: Install dependencies
	shell: bash -l {0}
	run: \|
	pip install .
	- name: Build XGBoost
	shell: bash -l {0}
	# yamllint disable rule:line-length
	run: \|
	open-ce build env xgboost-env \
	--container_build \
	--python_versions ${{ matrix.python-version }} \
	--build_types cpu
	# yamllint enable rule:line-length

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