Make sure to glob the correct files in CEM

Author: koddsson

custom-elements-manifest.config.js

@@ -3,9 +3,6 @@ import {readme} from '@github/cem-plugin-readme'
 
 export default {
   packagejson: true,
-  globs: ['src/index.ts'],
-  plugins: [
-    readme(),
-    generateCustomData()
-  ]
+  globs: ['src/*-element.ts'],
+  plugins: [readme(), generateCustomData()]
 }