Upgrade GitHub Actions for Node 24 compatibility

Author: salmanmkc

.github/workflows/_create_gke_cluster_xpk.yml

@@ -51,7 +51,7 @@ jobs:
     runs-on: gke-a3mega
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
 
     - name: Set workload name
       shell: bash -x -e -u {0}

.github/workflows/jax-vllm-offloading-eks-transfer.yml

@@ -18,7 +18,7 @@ jobs:
       MODEL: "meta-llama/Llama-3.1-8B-Instruct"
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
 
     - name: Login to GitHub Container Registry
       uses: docker/login-action@v3