v0.8.0

• firebase-admin peer dependency is now v5.6.0. Must update firebase-admin version inside of your functions directory's package.json and re-install locally.
• For Firestore events where no previous data exists, event.data.previous is no longer null, it is always a Firebase DocumentSnapshot. event.data.previous.exists will be false if there is no previous data. (This change was previously released in v0.7.4, and reverted in v0.7.5.)