added test for swift hook

testing/resources/swift_hooks_repo/.gitignore

@@ -0,0 +1,4 @@
+.DS_Store
+/.build
+/Packages
+/*.xcodeproj

testing/resources/swift_hooks_repo/Package.swift

@@ -0,0 +1,5 @@
+import PackageDescription
+
+let package = Package(
+    name: "swift_hooks_repo"
+)

testing/resources/swift_hooks_repo/Sources/main.swift

@@ -0,0 +1 @@
+print("Hello, world!")

testing/resources/swift_hooks_repo/hooks.yaml

@@ -0,0 +1,6 @@
+-   id: swift-hooks-repo
+    name: Swift hooks repo example
+    description: Runs the hello world app generated by swift package init --type executable (binary called swift_hooks_repo here)
+    entry: swift_hooks_repo
+    language: swift
+    files: \.(swift)$