Fix Twitter image (jhipster#1083)

Author: Matt Raible

_layouts/default.html

@@ -10,7 +10,7 @@
     <meta name="twitter:site" content="@jhipster" />
     <meta name="twitter:title" content="JHipster - Full Stack Platform for the Modern Developer!" />
     <meta name="twitter:description" content="JHipster is a development platform to quickly generate, develop, and deploy modern web applications + microservice architectures." />
-    <meta name="twitter:image:src" content="https://www.jhipster.tech/images/twitter-card.png?20210212" />
+    <meta name="twitter:image" content="https://www.jhipster.tech/images/twitter-card.png?20210212" />
     <meta name="twitter:url" content="https://www.jhipster.tech/" />{% endif %}
     <meta name="google-site-verification" content="JSA7VC5gSwD5KKbXlxK8F9rXJtC91rKJq0aWhfpBC0k" />
     <!-- Chrome, Firefox OS and Opera -->