Rename grpc metadata attribute names to reflect that they are grpc-sp…

…ecific (open-telemetry#2981)

CHANGELOG.md

@@ -30,6 +30,9 @@ release.
 
 - Add IBM Cloud as a cloud provider.
   ([#2965](https://github.com/open-telemetry/opentelemetry-specification/pull/2965))
+- Rename `rpc.request.metadata.<key>` and `rpc.response.metadata.<key>` to
+  `rpc.grpc.request.metadata.<key>` and `rpc.grpc.response.metadata.<key>`
+  ([#2981](https://github.com/open-telemetry/opentelemetry-specification/pull/2981))
 
 ### Compatibility
 

specification/trace/semantic_conventions/rpc.md

@@ -207,8 +207,8 @@ The [Span Status](../api.md#set-status) MUST be left unset for an `OK` gRPC stat
 
 | Attribute                     | Type     | Description                                                                                                                                                       | Examples                                                                   | Requirement Level |
 |-------------------------------|----------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------|-------------------|
-| `rpc.request.metadata.<key>`  | string[] | gRPC request metadata, `<key>` being the normalized gRPC Metadata key (lowercase, with `-` characters replaced by `_`), the value being the metadata values. [1]  | `rpc.request.metadata.my_custom_metadata_attribute=["1.2.3.4", "1.2.3.5"]` | Optional          |
-| `rpc.response.metadata.<key>` | string[] | gRPC response metadata, `<key>` being the normalized gRPC Metadata key (lowercase, with `-` characters replaced by `_`), the value being the metadata values. [1] | `rpc.response.metadata.my_custom_metadata_attribute=["attribute_value"]`   | Optional          |
+| `rpc.grpc.request.metadata.<key>`  | string[] | gRPC request metadata, `<key>` being the normalized gRPC Metadata key (lowercase, with `-` characters replaced by `_`), the value being the metadata values. [1]  | `rpc.request.metadata.my_custom_metadata_attribute=["1.2.3.4", "1.2.3.5"]` | Optional          |
+| `rpc.grpc.response.metadata.<key>` | string[] | gRPC response metadata, `<key>` being the normalized gRPC Metadata key (lowercase, with `-` characters replaced by `_`), the value being the metadata values. [1] | `rpc.response.metadata.my_custom_metadata_attribute=["attribute_value"]`   | Optional          |
 
 **[1]:** Instrumentations SHOULD require an explicit configuration of which metadata values are to be captured.
 Including all request/response metadata values can be a security risk - explicit configuration helps avoid leaking sensitive information.