CI: Update to checkout action v4 in aio job

Co-authored-by: Alex-Welsh <[email protected]>

Author: markgoddard

.github/workflows/stackhpc-all-in-one.yml

@@ -87,7 +87,7 @@ jobs:
     steps:
       # If testing upgrade, checkout previous release, otherwise checkout current branch
       - name: Checkout ${{ inputs.upgrade && 'previous release' || 'current' }} config
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           ref: ${{ inputs.upgrade && env.PREVIOUS_BRANCH || github.ref }}
           submodules: true
@@ -287,7 +287,7 @@ jobs:
         if: inputs.upgrade
 
       - name: Checkout current release config
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           submodules: true
           clean: false