Update CI config (#132)

Author: wojtekmach

.github/workflows/ci.yml

@@ -7,22 +7,8 @@ on:
   pull_request:
 
 jobs:
-  lint:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v2
-      - name: Install OTP and Elixir
-        uses: actions/setup-elixir@v1
-        with:
-          otp-version: "23.0"
-          elixir-version: "1.10.3"
-      - run: mix deps.get
-      - run: mix deps.unlock --check-unused
-      - run: MIX_ENV=test mix deps.compile
-      - run: MIX_ENV=test mix compile --warnings-as-errors
-      - run: mix format --check-formatted
   test:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-16.04
     strategy:
       matrix:
         db:
@@ -31,27 +17,47 @@ jobs:
           - mysql:8.0
           - mariadb:10.3
         pair:
-          - elixir: "1.10"
-            erlang: "23.0"
+          - elixir: 1.11.3
+            otp: 23.2.5
         include:
           - db: mysql:8.0
             pair:
-              elixir: "1.6.6"
-              erlang: "19.3.6.13"
+              elixir: 1.11.3
+              otp: 23.2.5
+            lint: lint
+          - db: mysql:8.0
+            pair:
+              elixir: 1.6.6
+              otp: 19.3.6.13
     env:
+      MIX_ENV: test
       DB: ${{matrix.db}}
       MYSQL_UNIX_PORT: /var/run/mysqld/mysqld.sock
     steps:
       - run: sudo mkdir -p /var/run/mysqld
       - run: sudo chmod 777 /var/run/mysqld
       - run: docker run -p 3306:3306 --volume /var/run/mysqld:/var/run/mysqld -e MYSQL_ALLOW_EMPTY_PASSWORD=1 --detach ${{matrix.db}} --innodb_log_file_size=1G
       - run: until mysql --port 3306 --protocol=tcp -u root -e "SELECT @@version;"; do sleep 3; done
+
       - uses: actions/checkout@v2
-      - uses: actions/setup-elixir@v1
+
+      - uses: erlef/setup-elixir@v1
         with:
-          otp-version: ${{matrix.pair.erlang}}
+          otp-version: ${{matrix.pair.otp}}
           elixir-version: ${{matrix.pair.elixir}}
-      - run: mix deps.get
-      - run: MIX_ENV=test mix deps.compile
-      - run: MIX_ENV=test mix compile
+
+      - name: Install Dependencies
+        run: mix deps.get --only test
+
+      - run: mix format --check-formatted
+        if: ${{ matrix.lint }}
+
+      - run: mix deps.get && mix deps.unlock --check-unused
+        if: ${{ matrix.lint }}
+
+      - run: mix deps.compile
+
+      - run: mix compile --warnings-as-errors
+        if: ${{ matrix.lint }}
+
       - run: mix test