Add strict values.schema.json to cyberchef

additionalProperties: false on every chart-owned object level, so a key
the chart does not read is rejected at render time instead of being
silently ignored. Objects passed verbatim into the pod spec (probes,
securityContext, global) stay open - Kubernetes owns their schema there.

Major bump: a schema can break existing deployments that carry dead keys.

Refs #68

cyberchef/Chart.yaml

@@ -5,7 +5,7 @@ icon: https://raw.githubusercontent.com/gchq/CyberChef/master/src/web/static/ima
 
 type: application
 
-version: 6.0.0+up11.4.0
+version: 7.0.0+up11.4.0
 appVersion: "11.4.0"
 
 maintainers: