chore(deps): Update the prometheus dependency of Loki and Promtail

[ptodev]

What this PR does / why we need it:

This PR updates the Prometheus dependency of Loki and Promtail. The PR is required so that we can also update Grafana Agent to the latest Prometheus. Unfortunately, Promtail and Loki share the same go.mod file. I am not able to update only Promtail.

Special notes for your reviewer:

• Is there a need to do any local testing? Or to add unit tests?
• Should I update any other go.mod files?
• The only user facing changes of this PR are that some metrics might change. Is this a problem?
  • Are there any dashboards and alerts which need to be updated?
  • Do I need to add a changelog entry?
  • Any updates to documentation? As far as I can tell, those metrics are not documented anywhere.
  • The metrics in pkg/ruler use a registry which is wrapped by labels such as user ID. I hope the cardinality of SD metrics won't increase too much now that the SD metrics will be using this wrapped registry too.

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• CHANGELOG.md updated
  • If the change is worth mentioning in the release notes, add add-to-release-notes label
• Changes that require user attention or interaction to upgrade are documented in docs/sources/setup/upgrade/_index.md
• For Helm chart changes bump the Helm chart version in production/helm/loki/Chart.yaml and update production/helm/loki/CHANGELOG.md and production/helm/loki/README.md. Example PR
• If the change is deprecating or removing a configuration option, update the deprecated-config.yaml and deleted-config.yaml files respectively in the tools/deprecated-config-checker directory. Example PR

[ptodev]

@chaudum I tested the Promtail code by running a local Promtail with this config:

Promtail config

server:
  http_listen_port: 9080
  grpc_listen_port: 0
  enable_runtime_reload: true
positions:
  filename: /Users/paulintodev/Desktop/log_metrics_bug/tmp_promtail/positions
clients:
  - url: ""
    basic_auth:
      username: ""
      password: ""
scrape_configs:
- job_name: log files
  consulagent_sd_configs:
  docker_sd_configs:
  file_sd_configs:
  static_configs:
  - labels:
      __path__: /Users/paulintodev/Desktop/log_metrics_bug/*.log

I also ran a Promtail using the code form the main, and compared the metrics which they expose on their http://localhost:9080/metrics endpoints. I found that all prometheus_sd_ and prometheus_target_ metrics are missing:

• new_metrics.txt
• old_metrics.txt

This is a correct side-effect of the latest Prometheus code. Promtail doesn't even use the Prometheus components which output those metrics, so I think it's safe to remove them.

I will need you to confirm a few things please:

• Given that the metrics we are removing are not used, I believe there is no need to update the docs?
• I am not sure if the changelog entry for this change will be descriptive enough. I guess I should mention in my commits that metrics which Promtail exposed are being removed?
• It would be nice if we could run a ruler, just to confirm that it runs ok and that its metrics haven't changed. Would this be very difficult?

[chaudum]

Thanks for tackling the Prometheus dependency upgrade!