Update actions/checkout from v4 to v6 for Node.js 24 compatibility

Author: merill

.github/workflows/publish-psmodule-preview.yml

@@ -14,7 +14,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Install Prerequisites
         run: .\build\powershell\Install-Prerequisites.ps1

.github/workflows/publish-psmodule-production.yml

@@ -9,7 +9,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Install Prerequisites
         run: .\build\powershell\Install-Prerequisites.ps1