fix: stringify json object based secrets

[Flydiverny]

When using an external secret like below where the secret value was formated like json you might expect to get the JSON value in the secret but instead you got "[object Object]"

apiVersion: kubernetes-client.io/v1
kind: ExternalSecret
metadata:
  name: secretsmanager-test
spec:
  backendType: secretsManager
  dataFrom:
    - /development/mma/dockerhub

Secret value:

{
  "auths": {
    "https://index.docker.io/v1/": {
      "auth": "bXktc2VjcmV0LWNyZWRlbnRpYWw6bm90LW15LXBhc3N3b3JkCg=="
    }
  }
}

Gave a secret like

apiVersion: v1
kind: Secret
metadata:
  name: secretmanager-test
data:
  auths: W29iamVjdCBPYmplY3Rd
type: Opaque

W29iamVjdCBPYmplY3Rd -> [object Object]

After this change:

eyJodHRwczovL2luZGV4LmRvY2tlci5pby92MS8iOnsiYXV0aCI6ImJYa3RjMlZqY21WMExXTnlaV1JsYm5ScFlXdzZibTkwTFcxNUxYQmhjM04zYjNKa0NnPT0ifX0= -> {"https://index.docker.io/v1/":{"auth":"bXktc2VjcmV0LWNyZWRlbnRpYWw6bm90LW15LXBhc3N3b3JkCg=="}}

[dawidmalina]

This is also what I'm looking for. @silasbw, @Flydiverny when this pull request will be merged and new version released?

[silasbw]

Sorry for the horrible response time on this.