Add deprecation warning (#75)

hughesjj · web-flow · commit ab31ff44ec5d · 2025-03-27T10:20:12.000-07:00
diff --git a/README.md b/README.md
@@ -1,5 +1,7 @@
 >ℹ️&nbsp;&nbsp;SignalFx was acquired by Splunk in October 2019. See [Splunk SignalFx](https://www.splunk.com/en_us/investor-relations/acquisitions/signalfx.html) for more information.
 
+>⚠️This plugin is no longer supported and will be archived by September 2025
+
 SignalFx Metadata Plugin
 ==============================
 
