Add triggers to Cloud Functions v2

[wiktorn]

• (incompatibile change) change structure for trigger_config and create substructures for v1 Cloud Functions and v2
• (incompatibile change) rename bucket_config.lifecycle_delete_age to bucket_config,lifecycle_delete_age_days
• (incompatibile change) rename function_config.instances to function_config.instance_count
• (incompatibile change) rename function_config.memory to function_config.memory_mb
• (incompatibile change) rename function_config.timeout to function_config.timeout_seconds
• add optional for objects in variables.tf
• make examples in README runable as tests
• add example for Cloud Function v2
• add example for trigger for Cloud Function v2
• remove optional variables from examples with null value
• assign IAM bindings to function based on version
• bump default Python version to 3.10

Closes #973

[ludoo]

A couple minor comments and a doubt which can be ignored, but good to go many thanks!

[wiktorn]

@juliocc @ludoo the only feature I also consider for this, is to also support creation of trigger service accounts. As you can notice in example - caller needs to specify service account for trigger by themselves.

I can add create_service_account = optional(bool, true) in v2 trigger_config and grant roles/run.invoker by default. This will help network-dashboard blueprint (that's my guess, why it's not working with V2 CF and requires ALLOW_ALL).

The other thing that I guess we could improve here is to provide option to specify roles for Cloud Function service account. Though this kind of overlaps with iam attribute. Any thoughts on that?

[ludoo]

That looks like a good idea, up to you if you want to add it here or in a separate PR.

Julio was also thinking about splitting the module into a v1 and a v2 module, which kind of makes sense. Again, feel free to merge this and we can discuss it later, or split it now if it makes more sense to you.

BTW, you should see a merge button already, if that's not the case let us know.

[juliocc]

Julio was also thinking about splitting the module into a v1 and a v2 module, which kind of makes sense. Again, feel free to merge this and we can discuss it later, or split it now if it makes more sense to you.

Lets's discuss it. I've been thinking about it for a few days but tbh I don't know if it's a good idea.