Add support for SwiftPM

Author: dreampiggy

.gitignore

@@ -34,3 +34,7 @@ Carthage/Build
 # `pod install` in .travis.yml
 #
 Pods/
+
+# SwiftPM
+.swiftpm
+.build

Package.resolved

@@ -0,0 +1,34 @@
+// swift-tools-version:5.0
+// The swift-tools-version declares the minimum version of Swift required to build this package.
+
+import PackageDescription
+
+let package = Package(
+    name: "SDWebImageAVIFCoder",
+    platforms: [
+        .macOS(.v10_10), .iOS(.v8), .tvOS(.v9), .watchOS(.v2)
+    ],
+    products: [
+        // Products define the executables and libraries produced by a package, and make them visible to other packages.
+        .library(
+            name: "SDWebImageAVIFCoder",
+            targets: ["SDWebImageAVIFCoder"]),
+    ],
+    dependencies: [
+        // Dependencies declare other packages that this package depends on.
+        // .package(url: /* package url */, from: "1.0.0"),
+        .package(url: "https://github.com/SDWebImage/SDWebImage.git", from: "5.1.0"),
+        .package(url: "https://github.com/SDWebImage/libavif-Xcode.git", from: "0.5.0")
+    ],
+    targets: [
+        // Targets are the basic building blocks of a package. A target can define a module or a test suite.
+        // Targets can depend on other targets in this package, and on products in packages which this package depends on.
+        .target(
+            name: "SDWebImageAVIFCoder",
+            dependencies: ["SDWebImage", "libavif"],
+            path: ".",
+            sources: ["SDWebImageAVIFCoder/Classes"],
+            publicHeadersPath: "SDWebImageAVIFCoder/Classes"
+        )
+    ]
+)

Package.swift

@@ -10,7 +10,7 @@
 #if __has_include(<libavif/avif.h>)
 #import <libavif/avif.h>
 #else
-#import "avif.h"
+#import "avif/avif.h"
 #endif
 
 // Convert 8/10/12bit AVIF image into RGBA8888