[AUTOMATIC] Release/5.16.1

[RCGitBot]

This is an automatic release.

RevenueCat SDK

🐞 Bugfixes

• Always call readyForPromotedProduct on main thread/actor (Always call readyForPromotedProduct on main thread/actor #4613) via Will Taylor (@fire-at-will)

RevenueCatUI SDK

🐞 Bugfixes

• Fix Gradient Preview on iOS 15 (Fix Gradient Preview on iOS 15 #4762) via Will Taylor (@fire-at-will)

🔄 Other Changes

• chore: Tweak default copy for dateWhenAppWasPurchased (chore: Tweak default copy for dateWhenAppWasPurchased #4703) via Facundo Menzella (@facumenzella)
• Rename RC Billing to Web Billing (Rename RC Billing to Web Billing #4734) via Antonio Borrero Granell (@antoniobg)
• Document Weak PurchasesDelegate Reference (Document Weak PurchasesDelegate Reference #4756) via Will Taylor (@fire-at-will)
• chore: A simple message for posterity (chore: A simple message for posterity #4758) via Facundo Menzella (@facumenzella)
• UI preview mode/always fetch offerings (UI preview mode/always fetch offerings #4754) via Antonio Pallares (@ajpallares)
• feat: Add tests for customer center events encoding (feat: Add tests for customer center events encoding #4739) via Facundo Menzella (@facumenzella)
• UI Preview Mode: add extra header to network requests (UI Preview Mode: add extra header to network requests #4752) via Antonio Pallares (@ajpallares)
• chore: Avoid gemfile.lock updates by fixing dependencies (chore: Avoid gemfile.lock updates by fixing dependencies #4694) via Facundo Menzella (@facumenzella)
• UI Preview Mode: mock products (UI Preview Mode: mock products #4735) via Antonio Pallares (@ajpallares)
• [Paywalls] Add extra gradient previews ([Paywalls] Add extra gradient previews #4750) via Mark Villacampa (@MarkVillacampa)

[fire-at-will]

RevenueCat was released on Cocoapods successfully, but pushing RevenueCatUI to Cocoapods failed with the internal server error response, causing the push-revenuecatui-pod CI job to fail. However, searching for RevenueCatUI shows that it was actually released successfully after all, so I'll go ahead and approve + merge this PR 👍

Cocoapods failure:

Cocoapods search showing the 5.16.1 release: