bump scratch-audio for AudioEngine.decodeSoundPlayer

package.json

@@ -93,7 +93,7 @@
     "redux-mock-store": "^1.2.3",
     "redux-throttle": "0.1.1",
     "rimraf": "^2.6.1",
-    "scratch-audio": "0.1.0-prerelease.1528394075",
+    "scratch-audio": "0.1.0-prerelease.1528996828",
     "scratch-blocks": "0.1.0-prerelease.1528907522",
     "scratch-l10n": "3.0.20180611175036",
     "scratch-paint": "0.2.0-prerelease.20180614161221",