[bitnami/external-dns:] Follow Helm rbac best practices

[lazouz]

Description of the change
bitnami/external-dns : Follow Helm rbac best practices (https://helm.sh/docs/chart_best_practices/rbac/).
Enables the use of custom serviceAccount with custom clusteRole and clusterRoleBinding.

Benefits

• Enables the use of custom serviceAccount with custom clusteRole and clusterRoleBinding (was not possible).
• Follow Helm best practices (https://helm.sh/docs/chart_best_practices/rbac/).

Possible drawbacks

Changes in variables names : breaking changes

Applicable issues

Not known

Additional information

Checklist

• Chart version bumped in Chart.yaml according to semver.
• Variables are documented in the README.md
• Title of the PR starts with chart name (e.g. [bitnami/chart])
• If the chart contains a values-production.yaml apart from values.yaml, ensure that you implement the changes in both files

⚠️ Keep in mind that if you want to make changes to the kubeapps chart, please implement them in the kubeapps repository. This is only a synchronized mirror.

[juan131]

Hi @lazouz

Thanks so much for your PR!

As you mentioned, adopting these best practices implies including breaking changes. That means we will have to bump the major version of the chart, and provide users a workaround (under the "Upgrade" section of the README.md) so they can smoothly transition between major versions.

We are aware that sometimes our charts do not meet every Helm best practice, because some of the charts are prior to the existence of these best practices and adopting them has a price: backwards incompatibility.

That said, I am not saying we are rejecting your PR, but you need to play a little bit with the upgrade process and document it so we can accept it.

[juan131]

Thanks so much for implementing the suggestions to document how to upgrade this chart.

Approving your PR!

[bitnami-bot]

I have just updated the bitnami images with the latest known immutable tags:

• "docker.io/bitnami/external-dns:0.7.1-debian-10-r56"