[add] github actions

.github/workflows/ci.yml

@@ -0,0 +1,43 @@
+on:
+  push:
+    branches:
+    - master
+  pull_request:
+
+jobs:
+  test:
+    name: Test
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        vim:
+        - v8.2.1000
+        - v8.2.0000
+        - v8.1.0000
+        - v8.0.0000
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@main
+
+    - name: Setup Vim
+      uses: rhysd/action-setup-vim@v1
+      with:
+        version: ${{ matrix.vim }}
+
+    - name: Install Dependencies
+      run: | 
+        git clone https://github.com/junegunn/vader.vim.git
+        git clone https://github.com/vim-airline/vim-airline
+        find $PWD/autoload/airline/themes -name "*.vim" > themes.txt
+    - name: Run Test
+      run: |
+        vim --not-a-term -Nu <(cat << VIMRC
+        filetype off
+        set rtp+=vader.vim
+        set rtp+=vim-airline
+        set rtp+=.
+        set rtp+=after
+        filetype plugin indent on
+        syntax enable
+        VIMRC) -c 'Vader! test/*' > /dev/null