update docs with grafana section

docs/spec/v1beta1/provider.md

@@ -58,6 +58,7 @@ Notification providers:
 * Generic webhook
 * Opsgenie
 * Alertmanager
+* Grafana
 
 Git commit status providers:
 
@@ -118,7 +119,7 @@ kubectl create secret generic webhook-url \
 Note that the secret must contain an `address` field.
 
 The provider type can be: `slack`, `msteams`, `rocket`, `discord`, `googlechat`, `webex`, `sentry`,
-`telegram`, `lark`, `matrix`, `azureeventhub`, `opsgenie`, `alertmanager` or `generic`.
+`telegram`, `lark`, `matrix`, `azureeventhub`, `opsgenie`, `alertmanager`, `grafana` or `generic`.
 
 When type `generic` is specified, the notification controller will post the
 incoming [event](event.md) in JSON format to the webhook address.
@@ -405,6 +406,35 @@ spec:
 ```
 
 
+### Grafana
+
+Sends notifications to [grafana annotations api](https://grafana.com/docs/grafana/latest/http_api/annotations/) 
+if grafana has authentication configured it is recommended to use secretRef and include the API key. 
+To enable the annotations on a Dashboard its needed to enable the annotations with Tag `flux` on the Dashboard settings by.
+This can be be performed by doing the following steps:
+* Annotations > Query > Enable Match any
+* Annotations > Query > Tags (Add Tag: `flux`)
+
+
+```shell
+kubectl create secret generic grafana-token \
+--from-literal=token=<grafana-api-key> \
+--from-literal=address=https://<grafana-url>/api/annotations
+```
+
+Then reference the secret in `spec.secretRef`:
+
+```yaml
+apiVersion: notification.toolkit.fluxcd.io/v1beta1
+kind: Provider
+metadata:
+  name: grafana
+  namespace: default
+spec:
+  type: grafana
+  secretRef:
+    name: grafana-token
+```
 ### Git commit status
 
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