Use actions/checkout@v4 in tzdata-update.yml.

Author: asfernandes

.github/workflows/tzdata-update.yml

@@ -18,7 +18,7 @@ jobs:
           - v4.0-release
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           ref: ${{ matrix.branch }}