wip: Split macOS and Linux GHA into separate jobs

Add concurrency  setting to GHS so only one will run at a time

.github/workflows/swift.yml

@@ -13,14 +13,18 @@ on:
   pull_request:
     branches: [ "main" ]
 
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
-  build:
-    name: Build and test on ${{ matrix.os }}
-    runs-on: ${{ matrix.os }}
+  macos:
     strategy:
       matrix:
-        os: [macos-14, ubuntu-latest]
+        os: [macos-14]
 
+    name: Build and test on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
     steps:
     - uses: swift-actions/setup-swift@v2
       with:
@@ -48,4 +52,39 @@ jobs:
       with:
         name: Swift tests on ${{ matrix.os }}
         path: results.xml
-        reporter: java-junit
+        reporter: java-junit
+
+  ubuntu:
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
+
+    name: Build and test on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    container: swiftlang/swift:nightly-6.0-jammy
+    steps:
+    - uses: actions/checkout@v3
+    - name: Get swift version
+      run: swift --version
+    - name: Get macOS version
+      run: sw_vers
+      if: startsWith( matrix.os, 'macos' )
+    - name: Set TEST_GITHUB_TOKEN env variable
+      shell: bash
+      env:
+        TEST_GITHUB_TOKEN: ${{ secrets.TEST_GITHUB_TOKEN }}
+      run: |
+        echo "$TEST_GITHUB_TOKEN" > $HOME/.env
+    - name: Build
+      run: swift build --build-tests
+    - name: Run tests
+      run: swift test --parallel --xunit-output=results.xml
+    - name: Report test results
+      uses: phoenix-actions/test-reporting@v8
+      id: test-report
+      if: success() || failure()    # run this step even if previous step failed
+      with:
+        name: Swift tests on ${{ matrix.os }}
+        path: results.xml
+        reporter: java-junit
+