This warning started popping up in Xcode 14:

warning: Run script build phase 'Crashlytics' will be run during every build because it does not specify any outputs. To address this warning, either add output dependencies to the script phase, or configure it to run in every build by unchecking "Based on dependency analysis" in the script phase.

The solution in the case of Crashlytics is to uncheck the Based on dependency analysis option in the Build Phase Script. This is a valid fix for Crashlytics, as you probably want it to run on every single build, incremental builds included.