Fixing namespace of HelmRepository in installation docs

[steve-fraser]

The documentation has the following config. The namespace of the HelmRepo is located in the flux-system and HelmRelease.spec.chart.sourceRef.Namespace is not configured

apiVersion: source.toolkit.fluxcd.io/v1beta2
kind: HelmRepository
metadata:
  name: flagger
  namespace: flux-system
spec:
  interval: 1h
  url: oci://ghcr.io/fluxcd/charts
  type: oci
---
apiVersion: helm.toolkit.fluxcd.io/v2beta1
kind: HelmRelease
metadata:
  name: flagger
  namespace: flagger-system
spec:
  interval: 1h
  releaseName: flagger
  install: # override existing Flagger CRDs
    crds: CreateReplace
  upgrade: # update Flagger CRDs
    crds: CreateReplace
  chart:
    spec:
      chart: flagger
      version: 1.x # update Flagger to the latest minor version
      interval: 1m # scan for new versions every six hours
      sourceRef:
        kind: HelmRepository
        name: flagger
      verify: # verify the chart signature with Cosign keyless
        provider: cosign 
  values:
    nodeSelector:
      kubernetes.io/os: linux

[stefanprodan]

LGTM

Thanks @steve-fraser