[bitnami/keycloak] Include image.tag value in Keycloak README.md

[EddyMM]

Description of the change

Explicitly mention in the README.md that the image tag for a custom Keycloak image can be specified using the image.tag value.

Including the tag in the image.repository value results in the helm chart's image.tag value overwriting it.

Without Tag:

image:
  repository: docker.io/../custom-keycloak:26.1.0

Helm Diff:

image: docker.io/.../custom-keycloak:26.1.0-debian-12-r0

With Tag:

image:
  repository: docker.io/../custom-keycloak
  tag: 26.1.0

Helm Diff:

image: docker.io/.../custom-keycloak:26.1.0

Benefits

• Consumers of bitnami/keycloak will know which image value to use to specify (tag in this case) for the custom keycloak image they're using

Additional information

Checklist

• Chart version bumped in Chart.yaml according to semver. This is not necessary when the changes only affect README.md files.
• Variables are documented in the values.yaml and added to the README.md using readme-generator-for-helm
• Title of the pull request follows this pattern [bitnami/<name_of_the_chart>] Descriptive title
• All commits signed off and in agreement of Developer Certificate of Origin (DCO)

[carrodher]

The image.tag field is omitted from the table with all the parameters on purpose to standardize the README for other products like Tanzu Application Catalog where those tags can point to different distros and not only Debian 12, see #19841.

[EddyMM]

Thanks for clarifying @carrodher . Is there any other documentation for someone to discover the image.tag if not from the README?

[carrodher]

All parameters are defined in the values.yaml, which provides a short explanation; see

charts/bitnami/keycloak/values.yaml

Line 102 in 8a2a477

## @skip image.tag Keycloak image tag (immutable tags are recommended)

In fact, that's the metadata used to autogenerate the table that appears in the README, so the information is the same.

[EddyMM]

Got it, thanks Carlos.