Featured Image 1.1.0

• Draft articles/pages and hidden articles/pages are now also processed (#8 by @Lucas-C)
• Fix error caused by articles containing <img> tags without src attributes (#9 by @Lucas-C)
• Python 3.9+ is now required (by @justinmayer)

Featured Image 1.0.0

• Rename plugin from “Representative Image” to “Featured Image”
• Convert to namespace plugin format and apply latest community standards
• Migrate from legacy repo to individual repo under Pelican Plugins organization