Set add_bucket_name_suffix to true by default

[vburckhardt]

Description

This is the right approach to avoid clashes. More advanced user can opt-out by setting this off while new users would get it out of the box. This is not a breaking change, but add a note in release notes to indicate to set this to false for existing buckets when moving up version.

[vburckhardt]

Seems the implementation is not complete - the root module was update to have this on by default, but it seems the buckets submodule was not updated ->

terraform-ibm-cos/modules/buckets/variables.tf

Line 11 in 3d6dafb

add_bucket_name_suffix = optional(bool, false)

Suggest to change this to true by default to align with root level COS module

Also suggest to avoid using chore prefix in commit for feature change. chore is for non-feature / non-consumer visible items.