Drop swift tools version (#212)

Author: noahsmartin

Package.swift

@@ -1,11 +1,11 @@
-// swift-tools-version: 5.9
+// swift-tools-version: 5.8
 // The swift-tools-version declares the minimum version of Swift required to build this package.
 
 import PackageDescription
 
 let package = Package(
     name: "SnapshotPreviews",
-    platforms: [.iOS(.v15), .macOS(.v12), .watchOS(.v10)],
+    platforms: [.iOS(.v15), .macOS(.v12), .watchOS(.v9)],
     products: [
         // Products define the executables and libraries a package produces, making them visible to other packages.
         .library(