add description in readme

Signed-off-by: Jennie Pham <[email protected]>

Author: ie-pham

charts/tempo-distributed/README.md

@@ -48,6 +48,13 @@ The command removes all the Kubernetes components associated with the chart and
 
 A major chart version change indicates that there is an incompatible breaking change needing manual actions.
 
+### From Chart versions < 1.32.0
+* Breaking Change *
+In order to reduce confusion, the overrides configurations have been renamed as below.  
+
+`global_overrides` =>  `overrides` (this is where the defaults for every tenant is set)
+`overrides` => `per_tenant_overrides` (this is where configurations for specific tenants can be set)
+
 ### From Chart versions < 1.31.0
 
 Tempo serverless was deprecated in [tempo 2.7 release](https://github.com/grafana/tempo/releases/tag/v2.7.0),