Update GitHub Actions to v4

Author: renovate[bot]

.github/workflows/ci.yml

@@ -7,9 +7,9 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Set up JDK 1.8
-        uses: actions/setup-java@v1
+        uses: actions/setup-java@v4
         with:
           java-version: 1.8
       - name: Build
@@ -18,7 +18,7 @@ jobs:
   renovate:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: 🧼 lint renovate config # Validates changes to renovate.json config file
         uses: suzuki-shunsuke/github-action-renovate-config-validator@v0.1.2
         with: