Strict flag for values

Helmwave will fail when file does not exist.

cat helmwave.yml

version: 0.23.1

repositories:
  - name: bitnami
    url: https://charts.bitnami.com/bitnami

.options: &options
  namespace: my-namespace
  wait: true

releases:
  - name: nginx
    <<: *options
    chart: bitnami/nginx
    values:
      - src: this_file_does_not_exist.yml
        strict: true