ci: set up

.github/workflows/ci.yml

@@ -0,0 +1,37 @@
+name: CI
+on:
+  pull_request:
+  push:
+
+jobs:
+  main:
+    runs-on: ubuntu-22.04
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - elixir: '1.17'
+            erlang: '27.0'
+            lint: true
+          - elixir: '1.16'
+            erlang: '26.2.5'
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/cache@v4
+        if: ${{ ! matrix.lint }}
+        with:
+          path: |
+            _build
+            deps
+          key: ${{ runner.os }}-${{ matrix.elixir }}-${{ matrix.erlang }}-${{ hashFiles('mix.lock') }}
+      - uses: erlef/setup-beam@v1
+        with:
+          otp-version: ${{ matrix.erlang }}
+          elixir-version: ${{ matrix.elixir }}
+      - run: mix deps.get --check-locked
+      - run: mix format --check-formatted
+        if: ${{ matrix.lint }}
+      - run: mix deps.unlock --check-unused
+        if: ${{ matrix.lint }}
+      - run: mix compile --warnings-as-errors
+      - run: mix test

mix.exs

@@ -5,7 +5,7 @@ defmodule TowerEmail.MixProject do
     [
       app: :tower_email,
       version: "0.1.0",
-      elixir: "~> 1.17",
+      elixir: "~> 1.16",
       start_permanent: Mix.env() == :prod,
       deps: deps()
     ]