update github actions version (#32)

.github/workflows/ci.yml

@@ -3,29 +3,29 @@ name: Continuous Integration
 on:
   pull_request:
   push:
-    branches: main
+    branches: [main]
 
 jobs:
   build:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node-version: [12.x]
+        node-version: [18.x]
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
 
     - name: Use Node.js ${{ matrix.node-version }}
-      uses: actions/setup-node@v2
+      uses: actions/setup-node@v4
       with:
         node-version: ${{ matrix.node-version }}
 
     - name: Get Yarn cache directory
       id: yarn-cache-dir-path
-      run: echo "::set-output name=dir::$(yarn cache dir)"
+      run: echo "dir=$(yarn cache dir)" >> $GITHUB_OUTPUT
 
     - name: Use Yarn cache
-      uses: actions/cache@v2
+      uses: actions/cache@v4
       id: yarn-cache
       with:
         path: ${{ steps.yarn-cache-dir-path.outputs.dir }}