Allow manifest to be async function or promise

Author: razor-x

lib/index.js

@@ -7,7 +7,11 @@ const createIo = require('./io')
 const normalize = require('./normalize')
 const install = require('./install')
 
-module.exports = async manifest => {
+module.exports = async manifestOrFunction => {
+  const promiseForManifest = typeof manifestOrFunction === 'function'
+    ? manifestOrFunction()
+    : manifestOrFunction
+  const manifest = await promiseForManifest
   const ioType = process.env.CURATOR_IO || manifest.ioType
   const pkgType = process.env.CURATOR_PKG || manifest.pkgType
   const hostname = os.hostname()