Spike to default the scope from package.json

Author: jasonkarns

Diff for: src/authutil.ts

@@ -25,6 +25,9 @@ function writeRegistryToFile(
   if (!scope && registryUrl.indexOf('npm.pkg.github.com') > -1) {
     scope = github.context.repo.owner;
   }
+  if (!scope && namePrefix = require('./package').name.match('@[^/]+')) {
+    scope = namePrefix[0]
+  }
   if (scope && scope[0] != '@') {
     scope = '@' + scope;
   }