Add a sanity check before bumping provider version

### Body Recently we ran into an issue while releasing providers, that if the changelog already had the "to be released" version of the provider, the repo would go into a slightly weird state while updating the documentation. Some details from a DM: > the issue is that if I am marking release as 9.3.0 but 9.3.0 exist in the change log then the output is as I showed you.. all tagging is lost. ideally what we need to have is for the process to alert me that i asked to cut 9.3.0 but it's already exist. that way I can go and manually fix the change log then resume from that point The command that requires updates (for amazon) ``` breeze release-management prepare-provider-documentation amazon ``` ### Committer - [x] I acknowledge that I am a maintainer/committer of the Apache Airflow project.