Update to actions/checkout@v6

Author: jan.nijtmans

.github/workflows/linux-build.yml

@@ -30,7 +30,7 @@ jobs:
         working-directory: unix
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         timeout-minutes: 5
       - name: Install 32-bit dependencies if needed
         # Duplicated from above

.github/workflows/mac-build.yml

@@ -17,7 +17,7 @@ jobs:
         working-directory: macosx
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         timeout-minutes: 5
       - name: Prepare
         run: |
@@ -48,7 +48,7 @@ jobs:
         working-directory: unix
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         timeout-minutes: 5
       - name: Prepare
         run: |

.github/workflows/win-build.yml

@@ -28,7 +28,7 @@ jobs:
     # Using powershell means we need to explicitly stop on failure
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         timeout-minutes: 5
       - name: Init MSVC
         uses: ilammy/msvc-dev-cmd@v1
@@ -77,7 +77,7 @@ jobs:
           install: git mingw-w64-x86_64-toolchain make
         timeout-minutes: 10
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         timeout-minutes: 5
       - name: Prepare
         run: |