Add get bucket versioning

[clook]

Implement GetBucketVersioning

[harshavardhana]

what is the purpose of just adding GetBucketVersioning? @clook

[clook]

Hi @harshavardhana, the goal is to be able to get the versioning status of bucket (https://docs.aws.amazon.com/AmazonS3/latest/API/API_GetBucketVersioning.html).

Currently, I'm using https://github.com/aminueza/terraform-provider-minio which relies on minio-go but am unable to provision a bucket with versioning configuration. I could easily make a PR for https://github.com/aminueza/terraform-provider-minio if GetBucketVersioning is supported.

[harshavardhana]

Currently, I'm using https://github.com/aminueza/terraform-provider-minio which relies on minio-go but am unable to provision a bucket with versioning configuration. I could easily make a PR for https://github.com/aminueza/terraform-provider-minio if GetBucketVersioning is supported.

@clook thanks for the explanation - it makes sense, but what is the pre-requisite of using bucket versioning with Terraform?

[clook]

@clook thanks for the explanation - it makes sense, but what is the pre-requisite of using bucket versioning with Terraform?

@harshavardhana The pre-requesite for the Terrraform provider is to be able to compare the Terraform current known state with the real resource state and then guess if it has to apply DisableVersioning or EnableVersioning or not.
Without knowing the real resource state, we would be forced to update the resource even if no change is necessary.

[clook]

Also tell me if you want some unit tests to be performed. Right now, I mostly templated over GetBucketEncryption and tested my branch with a PR on the actual Terraform provider.