refactor: use async/await syntax

src/index.js

@@ -1,13 +1,18 @@
 'use strict';
 
+// https://github.com/ipfs/js-ipfs/tree/ipfs%400.55.4/docs/core-api
 const IPFS = require('ipfs');
 
-IPFS.create().then(function(node) {
-    node.id().then(function(node_info) {
-        console.log('node id: ' + node_info.id);
-        const data = 'webpacked ' + node_info.agentVersion + ' ' + node_info.id + ' at ' + (new Date()).toISOString();
-        node.add(data).then(function(pin_info) {
-            console.log("https://ipfs.io/ipfs/" + pin_info.cid.toString());
-        });
-    });
-});
+async function initialize() {
+    const node = await IPFS.create();
+    const node_info = await node.id();
+    console.log('ipfs node id: ' + node_info.id);
+    const pin = await node.add(
+        'webpacked ' + node_info.agentVersion
+        + ' ' + node_info.id
+        + ' at ' + (new Date()).toISOString()
+    );
+    console.log("https://ipfs.io/ipfs/" + pin.cid.toString());
+}
+
+initialize();