update GH action for tests

Author: mattpolzin

.github/workflows/tests.yml

@@ -13,10 +13,6 @@ jobs:
       fail-fast: false
       matrix:
         image:
-          - swift:5.8-bionic
-          - swift:5.8-focal
-          - swift:5.8-jammy
-          - swift:5.8-amazonlinux2
           - swift:5.9-focal
           - swift:5.9-jammy
           - swift:5.9-amazonlinux2
@@ -25,14 +21,15 @@ jobs:
     - name: Checkout code
       uses: actions/checkout@v3
     - name: Run tests
-      run: swift test --enable-test-discovery
+      run: swift test
   osx:
-    runs-on: macOS-latest
+    runs-on: macOS-13
     steps:
       - name: Select latest available Xcode
         uses: maxim-lobanov/setup-xcode@v1
-        with: { 'xcode-version': 'latest' }
+        with: 
+          xcode-version: latest
       - name: Checkout code
         uses: actions/checkout@v3
       - name: Run tests
-        run: swift test --enable-test-discovery
+        run: swift test