drone Provide for annotations to kubernetes service

[james-mcgoodwin]

This change allows the user to provide annotations to the k8s svc for drone.

In our case, we rely on service annotations to interact with GCP NEGs via a controller that reads them.

This adds to the templates/service.yaml an optional 'annotations' field that can be populated by the user, or left empty by default.

This shouldn't be conflaited with the ingress annotations. We specifically do not use k8s ingress and we should be able to articulate annotations for either, both, or none of the service/ingress resources.

[james-mcgoodwin]

Popping this commit message out since it changes a default value in values.yaml:

CI fails to pass because values.yaml contains an invalid null string. Running 'helm lint ./drone' fails Even calling helm lint with an additional '-f ./drone/ci/test-values.yaml' still fails to validate values.yaml

$  helm lint ./drone/ -f ./drone/ci/test-values.yaml
==> Linting ./drone/
[ERROR] values.yaml: - env.DRONE_SERVER_HOST: String length must be greater than or equal to 3

Error: 1 chart(s) linted, 1 chart(s) failed

I have updated values.yaml with the example string used in the drone documentation page for the DRONE_SERVER_HOST value: https://readme.drone.io/server/reference/drone-server-host/

[cognifloyd]

values.schema.json needs an entry for service.annotations as well.

[jimsheldon]

Apologies for the delay on this. I agree it would be valuable to be able to set annotations on the service. If you can resolve the conflicts, I will review. Thanks!

[outergod]

I'm also affected by this and would love to see it resolved.

[jimsheldon]

78 will add this feature, closing this PR.