Release notes for Grafana 8.2.0

AWS: Updated AWS authentication documentation. #39236, @sunker
Alerting: Added support Alertmanager data source for upstream Prometheus AM implementation. #39775, @domasx2
Alerting: Allows more characters in label names so notifications are sent. #38629, @gotjosh
Alerting: Get alert rules for a dashboard or a panel using /api/v1/rules endpoints. #39476, @gerobinson
Annotations: Improved rendering performance of event markers. #39984, @torkelo
CloudWatch Logs: Skip caching for log queries. #39860, @aocenas
Explore: Added an opt-in configuration for Node Graph in Jaeger, Zipkin, and Tempo. #39958, @connorlindsey
Packaging: Add stricter systemd unit options. #38109, @erdnaxe
Prometheus: Metrics browser can now handle label values with special characters. #39713, @gabor

CodeEditor: Ensure that we trigger the latest onSave callback provided to the component. #39835, @mckn
DashboardList/AlertList: Fix for missing All folder value. #39772, @hugohaggmark

In Grafana v8.2.0, this change can prevent the grafana-server service from starting on older versions of systemd, present on Ubuntu 18.04 and slightly older versions of Debian. If running one of those versions, please wait until v8.2.1 is released before upgrading. If you still want to upgrade or have already upgraded, a simple fix is available here: https://github.com/grafana/grafana/issues/40162#issuecomment-938060240 Issue #38109