Update checkout action version. (#15)

.github/workflows/build.yml

@@ -9,12 +9,12 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Builder
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           path: build
           ref: build
       - name: Checkout Data
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           path: data
           ref: master