ci: update actions/checkout in GHA workflows to v6

Author: striezel

.github/workflows/alpine.yml

@@ -15,7 +15,7 @@ jobs:
           git config --global --add safe.directory "$GITHUB_WORKSPACE"
       # Checks-out the repository under $GITHUB_WORKSPACE.
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0
           submodules: 'recursive'

.github/workflows/alpine_arm.yml

@@ -30,7 +30,7 @@ jobs:
           rm -rf node20/*
           mkdir node20/bin
           ln -s /usr/bin/node node20/bin/node
-          # Fake Node.js 24 for actions/checkout@v5.
+          # Fake Node.js 24 for actions/checkout@v6.
           # Currently, Alpine 3.22 has Node.js 22.16.0, but that seems to work,
           # too, because it looks like checkout is not using any stuff specific
           # to Node.js 24.
@@ -39,7 +39,7 @@ jobs:
           ln -s /usr/bin/node node24/bin/node
       # Checks-out the repository under $GITHUB_WORKSPACE.
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0
           submodules: 'recursive'

.github/workflows/clang.yml

@@ -12,7 +12,7 @@ jobs:
     steps:
       # Checks-out the repository under $GITHUB_WORKSPACE.
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           submodules: 'recursive'
           persist-credentials: false

.github/workflows/gcc.yml

@@ -12,7 +12,7 @@ jobs:
     steps:
       # Checks-out the repository under $GITHUB_WORKSPACE.
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           submodules: 'recursive'
           persist-credentials: false

.github/workflows/msys2.yml

@@ -11,7 +11,7 @@ jobs:
     steps:
       # Checks-out the repository under $GITHUB_WORKSPACE.
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0
           submodules: 'recursive'