gh actions: add dialyzer and more #3

	# This workflow uses actions that are not certified by GitHub.
	# They are provided by a third-party and are governed by
	# separate terms of service, privacy policy, and support
	# documentation.

	name: Elixir CI

	on:
	push:
	branches: [ "main" ]
	pull_request:
	branches: [ "main" ]

	permissions:
	contents: read

	jobs:
	build:

	name: Build and test
	runs-on: ubuntu-latest

	steps:
	- uses: actions/checkout@v3
	- name: Set up Elixir
	uses: erlef/setup-beam@61e01a43a562a89bfc54c7f9a378ff67b03e4a21 # v1.16.0
	with:
	elixir-version: '1.15.2' # [Required] Define the Elixir version
	otp-version: '26.0' # [Required] Define the Erlang/OTP version
	- name: Restore dependencies cache
	uses: actions/cache@v3
	with:
	path: deps
	key: ${{ runner.os }}-mix-${{ hashFiles('**/mix.lock') }}
	restore-keys: ${{ runner.os }}-mix-
	- name: Install dependencies
	run: mix deps.get
	- name: Check Formatting
	run: mix format --check-formatted
	- name: Run Credo
	run: mix credo --strict
	- name: Run tests
	run: mix test
	- name: Build docs
	run: mix docs
	- name: Retrieve PLT Cache
	uses: actions/cache@v1
	id: plt-cache
	with:
	path: priv/plts
	key: ${{ runner.os }}-${{ matrix.otp }}-${{ matrix.elixir }}-plts-${{ hashFiles(format('{0}{1}', github.workspace, '/mix.lock')) }}
	- name: Create PLTs
	if: steps.plt-cache.outputs.cache-hit != 'true'
	run: \|
	mkdir -p priv/plts
	mix dialyzer --plt
	- name: Run dialyzer
	run: mix dialyzer --no-check --halt-exit-status

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