CI: Use checkout@v4 (#1616)

Author: olleolleolle

.github/workflows/test.yml

@@ -49,7 +49,7 @@ jobs:
       run: |
         sudo apt-get update
         sudo apt-get install libyaml-dev
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: ruby/setup-ruby@v1
       with:
         ruby-version: ${{ matrix.ruby }}
@@ -66,7 +66,7 @@ jobs:
       run: |
         sudo apt-get update
         sudo apt-get install libyaml-dev
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: ruby/setup-ruby@v1
       with:
         ruby-version: 3