Update swift.yml

Author: scottrhoyt

.github/workflows/swift.yml

@@ -14,6 +14,9 @@ jobs:
     runs-on: macos-latest
     steps:
     - uses: actions/checkout@v4
+      with:
+        submodules: true
+        recursive: true
     - uses: swift-actions/setup-swift@v2
       with:
         swift-version: "6.1.0"