Add basic Bazel build/test CI matrix for Ubuntu #3

	name: Build/Test

	on:
	push:
	branches:
	- main
	tags:
	- "**"
	pull_request:
	branches:
	- main
	workflow_dispatch:

	# only run one build doc workflow at a time, cancel any running ones
	concurrency:
	group: ${{ github.workflow }}-${{ github.ref }}
	cancel-in-progress: true

	jobs:
	build_test:
	strategy:
	matrix:
	os:
	- ubuntu
	version:
	- 18.04
	- 20.04
	- 22.04
	runs-on: ${{ matrix.os }}
	steps:
	- uses: actions/checkout@v2
	- name: Build
	run: bazel build //...
	- name: Test
	run: bazel test //...

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