Generally, Chrome updates all of the extensions you've added in the background, so you shouldn't have to worry about manually updating Capture each time we release a new version.
However, there are times where you might need to force an update through - and this is really easy to do.
- Open a new tab in your browser, type in 'chrome://extensions' and hit enter.
- Next, check the version number next to Capture to see if it's the latest version
- If it needs updating, tick the box in the top-right to turn on Developer Mode
- Click the 'Update Extensions Now' button that appears underneath
All of your Chrome extensions will then update to the latest version, including Capture.