Release 1.21.0

Added

• Utexas NoPro – suppress “upgrade to pro version” messages

Dependency updates

• beyond-multisite: 1.17.1 -> 1.18.0
• ns-cloner-site-copier: 4.4.9.1 -> 4.4.9.2
• really-simple-ssl: 9.5.10 -> 9.5.11
• wordpress-seo: 27.5 -> 7.6