[promtail] update to 3.0.0

[mjnagel]

Updates:

• Promtail 3.0.0 (does not appear to be any chart changes needed?)
• Switches configmap-reload to new ghcr location
• Allows for enabling service without servicemonitor

Previously made these changes in https://github.com/grafana/helm-charts/pull/3026/files but with the 3.0.0 release moved them here.

[mjnagel]

@zanhsieh rebased this and fixed linting issues if you are able to take another look!

[jimmy-ungerman]

Would love to get this approved to match our Promtail installation to the Loki version

[zalegrala]

Thanks for the contribution.

[jkroepke]

@zalegrala @zanhsieh @mjnagel

This update introduces an invalid template. If Values.service.labels is empty, the template breaks.

---
# Source: opsstack/charts/promtail/templates/service-metrics.yaml

apiVersion: v1
kind: Service
metadata:
  name: release-name-promtail-metrics
  namespace: default
  labels:
    helm.sh/chart: promtail-6.16.0
    app.kubernetes.io/name: promtail
    app.kubernetes.io/instance: release-name
    app.kubernetes.io/version: "3.0.0"
    app.kubernetes.io/managed-by: Helm
    {}
  annotations:
    {}
spec:

results into an helm error:

Error: YAML parse error on opsstack/charts/promtail/templates/service-metrics.yaml: error converting YAML to JSON: yaml: line 11: did not find expected key

Use --debug flag to render out invalid YAML

[mjnagel]

@jkroepke I'll fix this shortly, thanks for bringing to my attention.