Don't require `nodePort` to template if none is specified

[jessebot]

Description of the change

The actual port that the NodePort type service uses can be automatically generated if no nodeport field is specified, as per the docs here: https://kubernetes.io/docs/concepts/services-networking/service/#type-nodeport

Benefits

We now use a with instead of an if to make the code a bit cleaner, instead of setting the nodePort to "" which I think may also be confusing and/or not work.

Possible drawbacks

none that I can think of, but always open to feedback :)

Applicable issues

• fixes #44

Additional information

The actual value of nil in values.yaml has to change, otherwise, it interprets the nil as a string.

Checklist

• [x] I have read the CONTRIBUTING.md doc.
• [x] DCO has been signed off on the commit.
• [x] Chart version bumped in Chart.yaml according to semver.
• [x] (optional) Parameters are documented in the README.md

[jessebot]

oh no, why are all these tests failing? 🤔 Looks like it's because of this error:

Service in version "v1" cannot be handled as a Service: json: cannot unmarshal string into Go struct field ServicePort.spec.ports.nodePort of type int32

Let me see if I can fix it locally...

[jessebot]

ok, the fix was remove the nil from the values.yaml for the nodePort helm parameter 👍