Use Xcode 16.1 to try to get catalyst to work

.github/workflows/ci.yml

@@ -18,7 +18,7 @@ jobs:
     name: Test
     runs-on: macOS-14
     env:
-      DEVELOPER_DIR: /Applications/Xcode_16.app
+      DEVELOPER_DIR: /Applications/Xcode_16.1_beta_2.app
     strategy:
       matrix:
         destination:
@@ -32,3 +32,16 @@ jobs:
       - uses: actions/checkout@v4
       - name: Test platform ${{ matrix.destination }}
         run: set -o pipefail && xcodebuild -scheme Lock -destination "${{ matrix.destination }}" test | xcbeautify
+
+  linux_test:
+    name: Test Linux
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Install swiftly
+        run: curl -L https://swiftlang.github.io/swiftly/swiftly-install.sh | bash -s -- -y
+      - name: Install the latest Swift toolchain
+        run: swiftly install latest
+      - name: Test
+        run: swift test