`CircleCI`: fixed iOS 15 simulator versions (#1509)
`CircleCI`: fixed iOS 15 simulator versions (#1509)

This fixes the following error:
> [12:36:21]: No simulators found that are equal to the version of specifier (15.2) and greater than or equal to the version of deployment target (0)
> [12:36:21]: Ignoring 'iPhone 12 (15.2)', couldn’t find matching simulator
> [12:36:21]: Couldn't find any matching simulators for '["iPhone 12 (15.2)"]' - falling back to default simulator
> [12:36:21]: Found simulator "iPhone 8 (14.5)"

Neither iOS 15 nor Integration Tests were actually running on iOS 15, probably since we switched to Xcode 13.3.
RevenueCat/purchases-ios,RevenueCat/purchases-ios,RevenueCat/purchases-ios,RevenueCat/purchases-ios,RevenueCat/purchases-ios