Allow parallel testing in CI

Author: fpseverino

.github/workflows/ci.yml

@@ -38,7 +38,7 @@ jobs:
         brew install mosquitto
         mosquitto -d -c mosquitto/config/mosquitto.conf
     - name: SPM tests
-      run: swift test --enable-code-coverage --no-parallel
+      run: swift test --enable-code-coverage
     - name: Upload coverage data
       uses: vapor/swift-codecov-action@v0.3
       with:
@@ -101,7 +101,7 @@ jobs:
       env:
         MOSQUITTO_SERVER: mosquitto
       run: |
-        swift test --enable-code-coverage --no-parallel
+        swift test --enable-code-coverage
     - name: Upload coverage data
       uses: vapor/swift-codecov-action@v0.3
       with: