ci: fix workflow

.github/workflows/elixir.yml

@@ -1,16 +1,22 @@
+name: elixir
+
 on:
   push:
   pull_request:
 
 jobs:
   test:
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        otp: ['22.x', '23.x']
+        elixir: ['1.10.x', '1.11.x']
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-elixir@v1
         with:
-          elixir-version: ['1.9.x', '1.10.x', '1.11.x']
-          otp-version: ['22.x', '23.x']
+          otp-version: ${{matrix.otp}}
+          elixir-version: ${{matrix.elixir}}
       - run: mix deps.get
       - run: mix test
 

README.md

@@ -1,6 +1,6 @@
 ## Timex
 
-[![Master](https://api.cirrus-ci.com/github/bitwalker/timex.svg?branch=master)](https://cirrus-ci.com/github/bitwalker/timex)
+[![Master](https://github.com/bitwalker/timex/workflows/elixir/badge.svg?branch=master)](https://github.com/bitwalker/timex/actions?query=workflow%3A%22elixir%22+branch%3Amaster) |
 [![Hex.pm Version](http://img.shields.io/hexpm/v/timex.svg?style=flat)](https://hex.pm/packages/timex)
 [![Coverage Status](https://coveralls.io/repos/github/bitwalker/timex/badge.svg?branch=master)](https://coveralls.io/github/bitwalker/timex?branch=master)