Tag external tests with @github-api

Aims to avoid issues with GitHub rate limits on CI

Author: swissspidy

features/plugin-install-github-latest.feature

@@ -1,5 +1,6 @@
 Feature: Install WordPress plugins from GitHub
 
+  @github-api
   Scenario: Verify that providing a plugin releases/latest GitHub URL will get the latest ZIP
     Given a WP install
     When I run `wp plugin install https://github.com/danielbachhuber/one-time-login/releases/latest`

features/plugin-install.feature

@@ -335,6 +335,7 @@ Feature: Install WordPress plugins
       """
     And the wp-content/plugins/pwa-manifest-short-name.php file should exist
 
+  @github-api
   Scenario: Install plugin from a GitHub Gist page URL
     Given a WP install
 

features/upgradables.feature

@@ -213,7 +213,7 @@ Feature: Manage WordPress themes and plugins
       | theme  | Theme     | moina                   | Moina                   | 1.1.2   | https://wordpress.org/themes/download/moina.1.1.2.zip                  | {CONTENT_DIR}/moina/style.css                                     |
       | plugin | Plugin    | category-checklist-tree | Category Checklist Tree | 1.2     | https://downloads.wordpress.org/plugin/category-checklist-tree.1.2.zip | {CONTENT_DIR}/category-checklist-tree/category-checklist-tree.php |
 
-  @require-wp-4.5
+  @require-wp-4.5 @github-api
   Scenario Outline: Caches certain GitHub URLs
     Given a WP install
     And I run `wp plugin delete --all`