Bump firebase-ios-sdk to 7.0.0

[uhooi]

References:

• https://github.com/firebase/firebase-ios-sdk/releases/tag/CocoaPods-7.0.0
• https://firebase.google.com/support/release-notes/ios#7.0.0
• https://github.com/uhooi/UhooiPicBook/issues/114

[github-actions[bot]]

👋 Thanks for reporting! Please PR :)

[uhooi]

firebase-ios-sdk 7.1.0 Released!!

• https://github.com/firebase/firebase-ios-sdk/releases/tag/CocoaPods-7.1.0
• https://firebase.google.com/support/release-notes/ios#7.1.0