fix: serviceMonitor port is a string not integer

[ChrisJBurns]

Failing to pass kubeconform checks internally

Description of the change

• forces port to be a string. before this change kubeconform failed with the following error:

stdin - ServiceMonitor backstage is invalid: problem validating schema. Check JSON formatting: jsonschema: '/spec/endpoints/0/port' does not validate with https://artifactory.ci.corp.tanium.com/artifactory/github/datreeio/CRDs-catalog/raw/main/monitoring.coreos.com/servicemonitor_v1.json#/properties/spec/properties/endpoints/items/properties/port/type: expected string, but got number

• splits test and lint steps due to confusion in actions showing both as "Lint Charts".

Existing or Associated Issue(s)

Additional Information

https://github.com/yannh/kubeconform

Checklist

• Chart version bumped in Chart.yaml according to semver.
• Variables are documented in the values.yaml and added to the README.md. The helm-docs utility can be used to generate the necessary content. Use helm-docs --dry-run to preview the content.
• JSON Schema generated.
• List tests pass for Chart using the Chart Testing tool and the ct lint command.

[ChrisJBurns]

@tumido @vinzscam @sabre1041

Just realised I only have reviewer privileges and not maintainer privileges 😄 so let me know if looks good so we can merge. This should also resolve what #241 aims to complete, but we haven't heard back from the author of the PR and it seems like a couple of people are keen for this fix.

[sabre1041]

LGTM