feat: migrate date fields from string to Firestore Timestamp

[EArminjon]

This PR aim to help fixing the following issue : #86

I didn't know what is the best practice to handle data migration from old extension using STRING to this new version using TIMESTAMP.

I'm pretty new to Firebase Extension :D.

[jefago]

Hi @EArminjon , thank you for the PR! We are debating internally how to handle this; the suggestion makes perfect sense but we don't want to break any existing integrations that might depend on this being stored as string.

[EArminjon]

Yep that is exactly the hard point, if firebase could support timestamp comparison with string that could save a lot of work.

If you have any contact, you can try to pressure :') !

[unxavi]

Why not storing this a new fields name? or maybe this should be a major release

[EArminjon]

I think for the moment a new field is good enough.

[EArminjon]

Maybe you can use the Firebase Extension onUpdate https://firebase.google.com/docs/extensions/reference/extension-yaml#lifecycle-events, this event is used when developers update the extension. A script will be run and can handle the migration.

If developer don't want regression : they can upgrade later i believe.

Cc @jefago

[EArminjon]

Date format could also be a param which can be selected by developer when initializing the extension :
"Which date format would you use: (string / Timestamp) ?"

https://firebase.google.com/docs/extensions/reference/extension-yaml#secret-params

[EArminjon]

Hello any news on this ?