ci: update actions/checkout@v3 to v4

Updatate the "checkout" action to fix the following warning:

 Node.js 16 actions are deprecated. Please update the following
 actions to use Node.js 20: actions/checkout@v3. [...]

Signed-off-by: Jerome Forissier <[email protected]>
Acked-by: Etienne Carriere <[email protected]>

.github/workflows/ci.yml

@@ -9,7 +9,7 @@ jobs:
     container: jforissier/optee_os_ci
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0 # full history so checkpatch can check commit IDs in commit messages
       - name: Update Git config
@@ -67,7 +67,7 @@ jobs:
           restore-keys: |
             builds-cache-
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - shell: bash
         run: |
           # build task
@@ -276,7 +276,7 @@ jobs:
           restore-keys: |
             qemuv8_check-cache-
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - shell: bash
         run: |
           # make check task
@@ -315,7 +315,7 @@ jobs:
           restore-keys: |
             qemuv8_xen_check-cache-
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - shell: bash
         run: |
           # make check task
@@ -348,7 +348,7 @@ jobs:
           restore-keys: |
             qemuv8_hafnium_check-cache-
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - shell: bash
         run: |
           # make check task
@@ -379,7 +379,7 @@ jobs:
           restore-keys: |
             qemuv8_check_bti_mte_pac-cache-
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - shell: bash
         run: |
           # make check task