Add postpublish scripts for all the subpackages so that they each publish a release to github

packages/assert/scripts/postpublish.js

@@ -0,0 +1,13 @@
+const postpublish_utils = require('../../../scripts/postpublish_utils');
+
+const subPackageName = '0xproject/assert';
+
+postpublish_utils.getLatestTagAndVersionAsync(subPackageName)
+    .then(function(result) {
+        const releaseName = subPackageName + ' v' + result.version;
+        const assets = [];
+        return postpublish_utils.publishReleaseNotes(result.tag, releaseName, assets);
+    })
+    .catch (function(err) {
+        throw err;
+    });