Use main version instead released versions for upstream dependencies.

[jkroepke]

Hi,

some people (prometheus-community/helm-charts#4854) complain that the dashboards in kube-prometheus-stack are not compatible with Grafana 12 due angular dependencies.

Upstream project solves the issue months ago,

• provider/mesh: fix end timestamp for unstarted silences prometheus/alertmanager#407
• Migrate dashboards to new grafonnet library prometheus/node_exporter#3147

but there are not released tags yet. Since the mixin are not part of the official project, it seems not quite useful to exclusively use stable tags.

I would recommend to switch to commit hashes from main branch to gain updates much faster.