app.kubernetes.io/version label value is rendered with an invalid character

[frossi-git]

What steps did you take and what happened:
I am upgrading Gatekeeper to v3.18.0 via Helm chart using Flux CD HelmRelease with the reconcileStrategy parameter set to Revision.
helm upgrade fails with the error:

ServiceAccount "gatekeeper-admin-upgrade-crds" is invalid: metadata.labels: Invalid value: "3.18.0+95f1806eb07f": a valid label must be an empty string or consist of alphanumeric characters, '-', '_' or '.', and must start and end with an alphanumeric character (e.g. 'MyValue', or 'my_value', or '12345', regex used for validation is '(([A-Za-z0-9][-A-Za-z0-9_.]*)?[A-Za-z0-9])?')

The label with the problematic value is app.kubernetes.io/version, which is created in the helm chart template _helpers.tpl.

What did you expect to happen:
The label value should be populated with accepted values only.
The character + should be converted to _ as it is done for the gatekeeper.chart value.

Anything else you would like to add:
[Miscellaneous information that will assist in solving the issue.]
I am submitting a PR for the fix that I tested.

Environment:

• Gatekeeper version: 3.18.0
• Kubernetes version: (use kubectl version): v1.31.3-gke.1006000