Proxy the Bitnami helm chart repository

[2022-05-31T09:59:02.716Z] + make preview
[2022-05-31T09:59:02.716Z] promote preview version 2022.2.0-26-g89faaac939-PR-1179
[2022-05-31T09:59:02.716Z] Context "pod" modified.
[2022-05-31T09:59:02.716Z] Installing plugin jx-preview version 0.0.177 for command jx preview from https://github.com/jenkins-x-plugins/jx-preview/releases/download/v0.0.177/jx-preview-linux-amd64.tar.gz into .local/plugins/bin
[2022-05-31T09:59:04.609Z] found PullRequest https://github.com/nuxeo/nos/pull/1179
[2022-05-31T09:59:05.173Z] using ingress sub domain -jenkins-nuxeo-nos-pr-1179.
[2022-05-31T09:59:05.173Z] upserted preview nuxeo-nos-pr-1179
[2022-05-31T09:59:05.173Z] passing env vars into helmfile: map[string]string****"APP_NAME":"nos", "DOCKER_REGISTRY":"gcr.io/build-jx-prod", "DOCKER_REGISTRY_ORG":"nuxeo", "PREVIEW_NAMESPACE":"jenkins-nuxeo-nos-pr-1179", "VERSION":"2022.2.0-26-g89faaac939-PR-1179"}
[2022-05-31T09:59:06.544Z] jenkins-nuxeo-nos-pr-1179: ERROR: I0531 09:59:06.326898    2431 request.go:655] Throttling request took 1.151466851s, request: GET:https://10.115.240.1:443/apis/networking.gke.io/v1beta2?timeout=32s
[2022-05-31T09:59:28.436Z] error: failed to helmfile sync: failed to run helmfile repos: failed to run 'helmfile --file preview/helmfile.yaml repos' command in directory '', output: 'Adding repo bitnami https://charts.bitnami.com/bitnami
[2022-05-31T09:59:28.436Z] in preview/helmfile.yaml: in .helmfiles[0]: in ../helmfiles/nos/helmfile.yaml: command "/home/jenkins/.local/bin/helm" exited with non-zero status:
[2022-05-31T09:59:28.436Z] 
[2022-05-31T09:59:28.436Z] PATH:
[2022-05-31T09:59:28.436Z]   /home/jenkins/.local/bin/helm
[2022-05-31T09:59:28.436Z] 
[2022-05-31T09:59:28.436Z] ARGS:
[2022-05-31T09:59:28.436Z]   0: helm (4 bytes)
[2022-05-31T09:59:28.436Z]   1: repo (4 bytes)
[2022-05-31T09:59:28.436Z]   2: add (3 bytes)
[2022-05-31T09:59:28.436Z]   3: bitnami (7 bytes)
[2022-05-31T09:59:28.436Z]   4: https://charts.bitnami.com/bitnami (34 bytes)
[2022-05-31T09:59:28.436Z]   5: --force-update (14 bytes)
[2022-05-31T09:59:28.436Z] 
[2022-05-31T09:59:28.436Z] ERROR:
[2022-05-31T09:59:28.436Z]   exit status 1
[2022-05-31T09:59:28.436Z] 
[2022-05-31T09:59:28.436Z] EXIT STATUS
[2022-05-31T09:59:28.436Z]   1
[2022-05-31T09:59:28.436Z] 
[2022-05-31T09:59:28.436Z] STDERR:
[2022-05-31T09:59:28.436Z]   WARNING: Kubernetes configuration file is group-readable. This is insecure. Location: /home/jenkins/.kube/config
[2022-05-31T09:59:28.436Z]   WARNING: Kubernetes configuration file is world-readable. This is insecure. Location: /home/jenkins/.kube/config
[2022-05-31T09:59:28.436Z]   Error: looks like "https://charts.bitnami.com/bitnami" is not a valid chart repository or cannot be reached: stream error: stream ID 1; INTERNAL_ERROR