Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/codeql-analysis.yml

@@ -39,7 +39,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       # Initializes the CodeQL tools for scanning.
       - name: Initialize CodeQL

.github/workflows/ossar-analysis.yml

@@ -20,7 +20,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       # Ensure a compatible version of dotnet is installed.
       # The [Microsoft Security Code Analysis CLI](https://aka.ms/mscadocs) is built with dotnet v3.1.201.