Bump actions/checkout from 2 to 4 (#904)

.github/workflows/deploy-docs.yml

@@ -16,7 +16,7 @@ jobs:
     # if: github.repository_owner == 'spring-cloud'
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           ref: docs-build
           fetch-depth: 1

.github/workflows/maven.yml

@@ -19,7 +19,7 @@ jobs:
         java: ["17"]
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Set up JDK ${{ matrix.java }}
         uses: actions/setup-java@v3
         with: