[android] add sign task

haxetool/project.js

@@ -103,8 +103,7 @@ class HaxeBuilder extends Builder {
                         'tools',
                         'platform-tools',
                         'build-tools;27.0.3',
-                        //'platforms;android-19',
-                        'platforms;android-26',
+                        'platforms;android-28',
                         //'ndk-bundle',
                         'lldb;3.1',
                         'cmake;3.6.4111459',
@@ -125,7 +124,12 @@ class HaxeBuilder extends Builder {
         switch (this.buildSystem) {
             case BuildSystem.OPENFL:
                 return this.haxe.openfl('build', this.platform, this.config, this.debug)
-                    .then(result => streamToPromise(result.pipe(vfs.dest(target))));
+                    .then(result => {
+                        if (this.platform === Platform.ANDROID && this.config.key) {
+                            result = result.pipe(this.android.sign(this.config.key.store, this.config.key.pass));
+                        }
+                        return streamToPromise(result.pipe(vfs.dest(target)));
+                    });
             case BuildSystem.HAXE:
                 return this.haxe.build(this.platform, this.config, this.debug)
                     .then(result => streamToPromise(result.pipe(vfs.dest(target))));