Update ci.yml to checkout submodules

Author: VeckoTheGecko

.github/workflows/ci.yml

@@ -38,6 +38,7 @@ jobs:
       - uses: actions/checkout@v4
         with:
           fetch-depth: 0
+          submodules: recursive
       - uses: actions/cache/restore@v4
         with:
           path: pixi.lock
@@ -64,6 +65,7 @@ jobs:
       - uses: actions/checkout@v4
         with:
           fetch-depth: 0
+          submodules: recursive
       - uses: actions/cache/restore@v4
         with:
           path: pixi.lock