Clean build dir

Author: bcomnes

script/release.js

@@ -4,6 +4,10 @@ const version = require("../package.json").releaseVersion;
 
 console.log("Building new release for ", version);
 
+console.log("Cleaning build folder");
+exec("rm -rf build");
+exec("mkdir -p build");
+
 exec("yarn");
 exec("yarn build");