Move /e2e -> /e2e-tests

e2e-tests/cypress/tests/plugins/post_incoming_webhook.js

@@ -0,0 +1,18 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+const axios = require('axios');
+
+module.exports = async ({url, data}) => {
+    let response;
+
+    try {
+        response = await axios({method: 'post', url, data});
+    } catch (err) {
+        if (err.response) {
+            response = err.response;
+        }
+    }
+
+    return {status: response.status, data: response.data};
+};