fix(loki/production/docker-compose): upgrade loki and grafana production image tags to 3.1.1

[qdm12]

What this PR does / why we need it: Because this is on the v3.1.x release branch and it still has v2.x.x image tags in the docker-compose.yml. This should also be reflected by updating the link for docker-compose.yaml in the documentation at https://grafana.com/docs/loki/latest/setup/install/docker/#install-with-docker-compose

Which issue(s) this PR fixes: No issue created

Special notes for your reviewer:

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• Title matches the required conventional commits format, see here
  • Note that Promtail is considered to be feature complete, and future development for logs collection will be in Grafana Alloy. As such, feat PRs are unlikely to be accepted unless a case can be made for the feature actually being a bug fix to existing behavior.
• 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

[CLAassistant]

All committers have signed the CLA.

[cyriltovena]

LGTM