Repo File Sync: Bump actions/checkout from 5 to 6 (#102)

synced local file(s) with
[microsoft/mu_devops](https://github.com/microsoft/mu_devops).

Signed-off-by: Project Mu UEFI Bot <[email protected]>
Co-authored-by: mu-automation[bot] <204385837+mu-automation[bot]@users.noreply.github.com>

Author: mu-automation[bot]

.github/workflows/publish-release.yml

@@ -19,7 +19,7 @@ jobs:
 
     steps:
       - name: Checkout Repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Validate Branch
         run: |