Update RFC 0008 milestones

Signed-off-by: Matheus Pimenta <matheuscscp@gmail.com>

rfcs/0008-custom-event-metadata-from-annotations/README.md

@@ -1,6 +1,6 @@
 # RFC-0008 Custom Event Metadata from Annotations
 
-**Status:** implementable
+**Status:** implemented
 
 <!--
 Status represents the current state of the RFC.
@@ -241,6 +241,8 @@ To disable the feature, do not use `event.toolkit.fluxcd.io/` as a prefix in Flu
 
 ## Implementation History
 
+* RFC implemented and generally available in Flux v2.5.
+
 <!--
 Major milestones in the lifecycle of the RFC such as:
 - The first Flux release where an initial version of the RFC was available.