Bump natsio/nats-box from 0.14.6 to 0.15.0 in /helm/charts/nats (#945)

Bumps natsio/nats-box from 0.14.6 to 0.15.0.

---
updated-dependencies:
- dependency-name: natsio/nats-box
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

helm/charts/nats/values.yaml

@@ -564,7 +564,7 @@ natsBox:
   container:
     image:
       repository: natsio/nats-box
-      tag: 0.14.6
+      tag: 0.15.0
       pullPolicy:
       registry: