Merge pull request integrations#345 from jakebiesinger-onduo/patch-1

Fix README to include envvar for acceptance tests.

README.md

@@ -99,6 +99,8 @@ In the organization you are using above, create the following test repositories:
 * `test-repo-template`
   * Configure the repository to be a [Template repository](https://help.github.com/en/github/creating-cloning-and-archiving-repositories/creating-a-template-repository)
 
+Export an environment variable corresponding to `GITHUB_TEMPLATE_REPOSITORY=test-repo-template`.
+
 ### GitHub users
 Export your github username (the one you used to create the personal access token above) as `GITHUB_TEST_USER`. You will need to export a
 different github username as `GITHUB_TEST_COLLABORATOR`. Please note that these usernames cannot be the same as each other, and both of them