Update actions/checkout action to v7

Author: renovate[bot]

.github/workflows/check-sdk-updates.yml

@@ -14,7 +14,7 @@ jobs:
     name: Check for updates
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
 
       - name: Check for new JDK versions
         id: jdk

.github/workflows/deploy.yml

@@ -11,7 +11,7 @@ jobs:
     outputs:
       matrix: ${{ steps.generate.outputs.matrix }}
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
 
       - name: Generate matrix from matrix.json
         id: generate
@@ -33,7 +33,7 @@ jobs:
       fail-fast: false
       matrix: ${{ fromJson(needs.matrix.outputs.matrix) }}
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
 
       - name: Extract versions from Dockerfile
         id: versions