Update ci.yml

Author: DanielVandH

.github/workflows/ci.yml

@@ -18,7 +18,7 @@ jobs:
         arch:
           - x64
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: julia-actions/setup-julia@v2
         with:
           version: ${{ matrix.version }}