[Infra] Update 'actions/checkout' version in 'update-cpp-sdk-on-release.yml' (#10702)

Author: ncooke3

.github/workflows/update-cpp-sdk-on-release.yml

@@ -26,7 +26,7 @@ jobs:
           python-version: 3.7
 
       - name: Check out firebase-cpp-sdk
-        uses: actions/checkout@v3.3.1
+        uses: actions/checkout@v3
         with:
           repository: firebase/firebase-cpp-sdk
           ref: main