Specify a version for the NGINX Ingress and Cert-Manager Operators

Summary

In our nginx-ingress and cert-manager operator subscriptions, we don't specify a version. In the past, this has lead to "surprise" updates which sometimes broke functionality.

To address this, we can specify a version in the Subscription objects linked above. For more information, see: https://docs.openshift.com/container-platform/4.5/operators/user/olm-installing-operators-in-namespace.html#olm-installing-specific-version-cli_olm-installing-operators-in-namespace

Acceptance criteria

• Specific versions for the cert-manager and NGINX-ingress operators are configured