setup CI in GitHub Actions

.github/workflows/ci.yaml

@@ -0,0 +1,32 @@
+name: CI
+
+on: [push, pull_request]
+
+jobs:
+  test:
+    name: Test
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        vim:
+        - v8.2.0000
+        - v8.1.0000
+        - v8.0.0000
+        - v7.4
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@master
+    - name: Checkout vim-themis
+      uses: actions/checkout@master
+      with:
+        repository: thinca/vim-themis
+        path: vim-themis
+    - name: Setup Vim
+      uses: rhysd/action-setup-vim@v1
+      id: vim
+      with:
+        version: ${{ matrix.vim }}
+    - name: Test
+      env:
+        THEMIS_VIM: ${{ steps.vim.outputs.executable }}
+      run: ./vim-themis/bin/themis --reporter spec

README.md

@@ -1,4 +1,4 @@
-# vim-haskell-indent [![Build Status](https://travis-ci.org/itchyny/vim-haskell-indent.svg)](https://travis-ci.org/itchyny/vim-haskell-indent)
+# vim-haskell-indent [![CI Status](https://github.com/itchyny/vim-haskell-indent/workflows/CI/badge.svg)](https://github.com/itchyny/vim-haskell-indent/actions)
 ## The best indent plugin for Haskell in Vim
 
 ![vim-haskell-indent](https://raw.githubusercontent.com/wiki/itchyny/vim-haskell-indent/image/1.gif)