Update changelog for previous revert and add `title` for img emoji

CHANGES.md

 # Changelog
 
+## 7.0.3 (Unreleased)
+
+- Bugfix: `null` inserted by emoji picker and can't switch between skintones
+
 ## 7.0.2 (2020-11-23)
 
 - Updated translations: de, nb, gl, tr

src/headless/converse-emoji.js

@@ -126,6 +126,7 @@ export function getEmojiMarkup (data, options={unicode_only: false, add_title_wr
                 const path = api.settings.get('emoji_image_path');
                 return html`<img class="emoji"
                     draggable="false"
+                    title="${shortname}"
                     alt="${emoji}"
                     src="${path}/72x72/${data.cp}.png"/>`;
             }