Update package-support docs with @google-cloud/vision workaround (#432

)

Add workaround for `@google-cloud/vision`

package-support.md

@@ -4,13 +4,31 @@ Packages that need specific configurations for ncc support are included below.
 
 If you are having trouble running a package with ncc, try searching for it in the [issue queue](https://github.com/zeit/ncc/issues) or posting an issue.
 
-### Sequelize
+### `sequelize`
 
 For example, with the `mariadb` dialect:
 
 ```js
+const Sequelize = require('sequelize');
 const db = new Sequelize({
   dialect: 'mariadb',
   dialectModule: require('mariadb')
 });
 ```
+
+The important part here is defining `dialectModule`.
+
+### `@google-cloud/vision`
+
+Add `google-proto-files` in your `package.json` dependencies.
+
+```json
+{
+  "name": "example",
+  "main": "index.js",
+  "dependencies": {
+    "@google-cloud/vision": "1.1.1",
+    "google-proto-files": "1.0.1"
+  }
+}
+```