Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/deploy-production.yml

@@ -15,7 +15,7 @@ jobs:
       contents: read
     steps:
       - name: Checkout repo
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Configure AWS credentials
         uses: aws-actions/configure-aws-credentials@v5

.github/workflows/deploy-staging.yml

@@ -17,7 +17,7 @@ jobs:
       contents: read
     steps:
       - name: Checkout repo
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Configure AWS credentials
         uses: aws-actions/configure-aws-credentials@v5

.github/workflows/test.yml

@@ -13,7 +13,7 @@ jobs:
       DATABASE_URL: postgres://bors:bors@localhost:5432/bors
     steps:
       - name: Checkout sources
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Start containers
         run: docker compose up -d --wait
@@ -50,7 +50,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repo
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - uses: docker/setup-buildx-action@v3
       - name: Build the Docker image
         uses: docker/build-push-action@v6