cocoapods could not find compatible versions for pod cloud_firestore flutter code example

Example 1: CocoaPods could not find compatible versions for pod "Firebase/Messaging":

I had the same problem, but I solved it like this

rm Podfile.lock
pod install --repo-update

Example 2: cocoapods could not find compatible versions for pod cloud_firestore

# platform :ios, '9.0'
change to 

platform :ios, '10.0'