Add Swift starter template

ci/properties/swift.properties.json

@@ -0,0 +1,6 @@
+{
+    "name": "Swift",
+    "description": "Build and test a Swift Package.",
+    "iconName": "swift",
+    "categories": ["Swift"]
+}

ci/swift.yml

@@ -0,0 +1,15 @@
+name: Swift
+
+on: [push]
+
+jobs:
+  build:
+
+    runs-on: macOS-latest
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: Build
+      run: swift build -v
+    - name: Run tests
+      run: swift test -v