Unity: None of your spec sources contain a spec satisfying the dependency: `Firebase/Analytics (= 10.0.0)`

We are trying to use Firebase Analytics but when we build our Unity project we get a CocoaPods installation failure:

None of your spec sources contain a spec satisfying the dependency: `Firebase/Analytics (= 10.0.0)`.
 
 You have either:
  * out-of-date source repos which you can update with `pod repo update` or with `pod install --repo-update`.
  * mistyped the name or version.
  * not added the source repo that hosts the Podspec to your Podfile.
 
 
 Ignoring ffi-1.13.1 because its extensions are not built. Try: gem pristine ffi --version 1.13.1
 Ignoring json-1.8.6 because its extensions are not built. Try: gem pristine json --version 1.8.6
 
 pod repo update output:
 
 Updating spec repo `cocoapods`
   $ /usr/bin/git -C /Users/josephhopkins/.cocoapods/repos/cocoapods fetch origin --progress
   $ /usr/bin/git -C /Users/josephhopkins/.cocoapods/repos/cocoapods rev-parse --abbrev-ref HEAD
   master
   $ /usr/bin/git -C /Users/josephhopkins/.cocoapods/repos/cocoapods reset --hard origin/master
   HEAD is now at 7b2edeb16678 [Add] SwiftCurrent 5.1.10
 Updating spec repo `trunk`
 
 CocoaPods 1.11.3 is available.
 To update use: `gem install cocoapods`
 
 For more information, see https://blog.cocoapods.org and the CHANGELOG for this version at https://github.com/CocoaPods/CocoaPods/releases/tag/1.11.3

We are using Unity 2020.3.8f1. We tried deleting the Library cache folder but error still happens. How do we fix this problem?