v4.2.1

Fixes

• Fetching article images (when using the --inline flag, or when producing EPUBs) now sends the Referer header as the browser would when rendering the article (using the strict-origin-when-cross-origin referrer policy) (#172). Note that when producing HTML or PDF documents of web pages containing images that require a Referer header, you’ll need to use the --inline flag.
• Use a fallback when slugifying an article title results in the empty string.