ci(GHA): use actions/checkout@v4

.github/workflows/callable-flex-cleanup.yml

@@ -11,7 +11,7 @@ jobs:
         steps:
             -
                 name: Checkout
-                uses: actions/checkout@v3
+                uses: actions/checkout@v4
 
             -
                 name: Cleanup Flex testing endpoint

.github/workflows/callable-flex-update-archived.yml

@@ -16,7 +16,7 @@ jobs:
         steps:
             -
                 name: Checkout
-                uses: actions/checkout@v3
+                uses: actions/checkout@v4
                 id: checkout
                 with:
                     fetch-depth: 0

.github/workflows/callable-flex-update.yml

@@ -22,7 +22,7 @@ jobs:
         steps:
             -
                 name: Checkout
-                uses: actions/checkout@v3
+                uses: actions/checkout@v4
                 id: checkout
                 with:
                     fetch-depth: 0