Refactor to be promise-based

.gitignore

@@ -1 +1,3 @@
 node_modules
+/.nyc_output/
+/coverage/

.travis.yml

@@ -1,8 +1,6 @@
 sudo: false
 language: node_js
 node_js:
-  - '9'
+  - '12'
+  - '10'
   - '8'
-  - '7'
-  - '6'
-  - '4'

README.md

@@ -29,6 +29,9 @@ rpt('/path/to/pkg/root', function (node, kidName) {
   //   error: <if set, the error we got loading/parsing the package.json>
   // }
 })
+
+// or promise-style
+rpt('/path/to/pkg/root').then(data => { ... })
 ```
 
 That's it.  It doesn't figure out if dependencies are met, it doesn't