add benchmark GHA #8

	name: benchmarks
	concurrency:
	group: ${{ github.workflow }}-${{ github.head_ref \|\| github.run_id }}
	cancel-in-progress: true
	on:
	pull_request:
	branches:
	- main
	paths-ignore:
	- 'LICENSE.md'
	- 'README.md'
	- 'docs/**'
	- 'issues/**'
	- 'format/**'
	- 'test/**'
	jobs:
	benchmarks:
	runs-on: ubuntu-latest
	strategy:
	fail-fast: false
	steps:
	- uses: actions/checkout@v3
	- uses: julia-actions/setup-julia@v1
	with:
	version: "1"
	- uses: julia-actions/cache@v1
	- uses: julia-actions/julia-buildpkg@v1
	- name: Benchmark run
	run: \|
	git fetch origin +:refs/remotes/origin/HEAD
	julia --project=benchmark/ -e '
	using Pkg
	Pkg.develop(PackageSpec(path=pwd()))
	Pkg.instantiate()'
	# Pkg.update() allows us to benchmark even when dependencies/compat requirements change
	julia --project=benchmark/ -e '
	using PkgBenchmark, MixedModels
	# explicit `Pkgadd` is a crutch until we've got a good base on main
	juliacmd = `$(Base.julia_cmd()) -O3 -e "using Pkg; Pkg.update(); Pkg.add([\"BenchmarkTools\", \"StatsModels\"])"`
	config = BenchmarkConfig(; id="origin/HEAD", juliacmd)
	export_markdown("benchmark.md", judge(MixedModels, config; verbose=true))'
	- name: Comment PR
	uses: thollander/actions-comment-pull-request@v2
	with:
	filePath: "benchmark.md"
	comment_tag: benchmark

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