Can't add items for NetworkPolicy

[twavv]

Reproduction:

# config.yaml
networkPolicy:
  enabled: true
  ingress:
    grpc: 
    - podSelector:
        matchLabels:
          foo: bar

helm lint --debug -n cockroachdb  ./cockroachdb -f ./config.yaml 
==> Linting ./cockroachdb
[ERROR] templates/: template: cockroachdb/templates/_helpers.tpl:14:14: executing "cockroachdb.fullname" at <.Values.fullnameOverride>: can't evaluate field Values in type []interface {}

Error: 1 chart(s) linted, 1 chart(s) failed
helm.go:75: [debug] 1 chart(s) linted, 1 chart(s) failed
main.newLintCmd.func1
        /private/tmp/helm-20200213-73045-zsskjg/src/helm.sh/helm/cmd/helm/lint.go:113
github.com/spf13/cobra.(*Command).execute
        /private/tmp/helm-20200213-73045-zsskjg/pkg/mod/github.com/spf13/[email protected]/command.go:826
github.com/spf13/cobra.(*Command).ExecuteC
        /private/tmp/helm-20200213-73045-zsskjg/pkg/mod/github.com/spf13/[email protected]/command.go:914
github.com/spf13/cobra.(*Command).Execute
        /private/tmp/helm-20200213-73045-zsskjg/pkg/mod/github.com/spf13/[email protected]/command.go:864
main.main
        /private/tmp/helm-20200213-73045-zsskjg/src/helm.sh/helm/cmd/helm/helm.go:74
runtime.main
        /usr/local/Cellar/go/1.13.8/libexec/src/runtime/proc.go:203
runtime.goexit
        /usr/local/Cellar/go/1.13.8/libexec/src/runtime/asm_amd64.s:135

Jira issue: HELM-42