Bump actions/checkout from 5 to 6 (#804)

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/build.yml

@@ -37,7 +37,7 @@ jobs:
         uses: crystal-lang/install-crystal@v1
 
       - name: Checkout source code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install dependencies
         run: shards install

.github/workflows/cd.yml

@@ -26,7 +26,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v3

.github/workflows/ci-base.yml

@@ -30,7 +30,7 @@ jobs:
           sudo apt-get install libxml2-utils -y
 
       - name: Download source
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install dependencies
         run: shards install