Block public access config should honor provider/deploymentBucket/blockPublicAccess or custom/deploymentBucket/blockPublicAccess

[philvarner]

serverless-deployment-bucket currently only honors the setting for Block Public Access configured by custom/deploymentBucket/blockPublicAccess, and ignore the same value used by the core serverless config at provider/deploymentBucket/blockPublicAccess.

The underlying issue here is that serverless-deployment-bucket requires a confusing configuration with respect to recent versions of serverless. I have not verified this theory by looking at the changelogs for serverless and serverless-deployment-bucket, but I believe that the blockPublicAccess configuration option was added to serverless-deployment-bucket prior to it being added to serverless, and each requires it to be in a different place in the configuration.

Without the plugin, serverless allows the configuration of the name of a pre-existing bucket or other parameters like Block Public Access to be set.

Use this pre-created bucket and do not alter it (e.g., if blockPublicAccess were set, it would be ignored)

provider:
  deploymentBucket:
    name: some-bucket

or, auto-create the bucket and set Block Public Access:

provider:
  deploymentBucket:
    blockPublicAccess: true

Confusingly, when using the serverless-deployment-bucket plugin, the provider/deploymentBucket/name field is used for the bucket name (creating it if it doesn't exist), but the provider/deploymentBucket/blockPublicAccess configuration is ignored and only the custom/deploymentBucket/blockPublicAccess is honored.

A correct configuration for using serverless-deployment-bucket will look like this:

plugins:
  - serverless-deployment-bucket
...
provider:
  deploymentBucket:
    name: slsdeploy-example-app-todos-dev
...
custom:
  deploymentBucket: # used by serverless-deployment-bucket
    blockPublicAccess: true