Add build docker image to CI (#7332)

* add build docker image to CI

* remove node setup

* removed local dependency to test passing docker build

* Update CHANGELOG.md

* Revert "removed local dependency to test passing docker build"

This reverts commit a7801e1874be206c9f3f7bfd367766546bf483b6.

* removed unnecessary docker build options

* fixed docker build

spec/support/MockMailAdapter/index.js

@@ -1,15 +0,0 @@
-/**
- * A mock mail adapter for testing.
- */
-class MockMailAdapter {
-  constructor(options = {}) {
-    if (options.throw) {
-      throw 'MockMailAdapterConstructor';
-    }
-  }
-  sendMail() {
-    return 'MockMailAdapterSendMail';
-  }
-}
-
-module.exports = MockMailAdapter;

spec/support/MockMailAdapter/package.json

@@ -1,6 +0,0 @@
-{
-  "name": "mock-mail-adapter",
-  "version": "1.0.0",
-  "description": "Mock mail adapter for tests.",
-  "main": "index.js"
-}