Add meta tags for twitter cards

Author: cvle

docs/src/index.html

@@ -7,6 +7,13 @@
   <meta property="og:description" content="Take Control of your CSS Transitions" />
   <meta property="og:url" content="https://wikiwi.github.io/react-css-transition/" />
   <meta property="og:image" content="https://wikiwi.github.io/react-css-transition/preview.png" />
+
+  <meta name="twitter:card" content="summary_large_image" />
+  <meta name="twitter:creator" content="@wikiwi_io" />
+  <meta name="twitter:title" content="React CSS Transition" />
+  <meta name="twitter:description" content="Take Control of your CSS Transitions" />
+  <meta name="twitter:image" content="https://wikiwi.github.io/react-css-transition/preview.png" />
+
   <meta http-equiv="Content-type" content="text/html; charset=utf-8" />
   <meta name="viewport" content="width=device-width" />
   <meta name="mobile-web-app-capable" content="yes" />