Loosens generated version of twilio-run.

It would be inefficient to keep updating this package as twilio-run updates.
'2.* || >2.0.0-rc' will pick the latest in the 2.* branch, otherwise falling back to the latest release candidate.

Fixes #18.

Author: philnash

src/create-twilio-function/versions.js

@@ -1,4 +1,4 @@
 module.exports = {
-  twilioRun: '^2.0.0-beta.11',
+  twilioRun: '2.* || >2.0.0-rc',
   node: '8.10.0'
 };