Support webp in linux os with aarch64 architecture (#286)

* Add webp binaries for linux-aarch64

* Detect linux os with aarch64 architecture

* Update README.md

linux-aarch64 binaries are included

docs/webp.md

@@ -5,7 +5,7 @@
 Scrimage provides support for webp through the `scrimage-webp` module. To use webp, add this module to your build.
 
 This module uses the `dwebp`, `cwebp` and `gif2webp` binaries, created by Google. The `scrimage-webp` module comes with the
-linux_x64, window_x64, mac-x64 and mac-arm64 binaries already included (see required [copyright notice](https://github.com/sksamuel/scrimage/blob/master/scrimage-webp/src/main/resources/dist_webp_binaries/LICENSE)).
+linux_x64, linux_aarch64, window_x64, mac-x64 and mac-arm64 binaries already included (see required [copyright notice](https://github.com/sksamuel/scrimage/blob/master/scrimage-webp/src/main/resources/dist_webp_binaries/LICENSE)).
 
 Note: If you are using mac-arm64 then you must specify the system-property: `com.sksamuel.scrimage.webp.platform=mac-arm64` because scrimage is unable to detect mac-x64 from mac-arm64, and defaults to the former.
 

scrimage-webp/src/main/java/com/sksamuel/scrimage/webp/WebpHandler.java

@@ -72,6 +72,8 @@ protected static String[] getBinaryPaths(String binaryName) {
          return macArm(binaryName);
       } else if (SystemUtils.IS_OS_MAC) {
          return macIntel(binaryName);
+      } else if (SystemUtils.IS_OS_LINUX && (osArch.startsWith("arm") || osArch.startsWith("aarch64"))) {
+         return linuxArm(binaryName);
       } else {
          return linux(binaryName);
       }
@@ -115,6 +117,14 @@ private static String[] linux(String binaryName) {
       };
    }
 
+   private static String[] linuxArm(String binaryName) {
+      return new String[]{
+         "/webp_binaries/" + binaryName,
+         "/webp_binaries/linux/" + binaryName,
+         "/dist_webp_binaries/libwebp-1.3.2-linux-aarch64/bin/" + binaryName,
+      };
+   }
+
    private static void setExecutable(Path output) throws IOException {
       try {
          new ProcessBuilder("chmod", "+x", output.toAbsolutePath().toString())