Add missing header to eth/v1/builder/blinded_blocks (#5407)

* add missing header

* read header in mock builder

* Merge branch 'unstable' into builder-blinded-blocks-missing-header

beacon_node/builder_client/src/lib.rs

@@ -5,7 +5,8 @@ use eth2::types::{
 };
 use eth2::types::{FullPayloadContents, SignedBlindedBeaconBlock};
 pub use eth2::Error;
-use eth2::{ok_or_error, StatusCode};
+use eth2::{ok_or_error, StatusCode, CONSENSUS_VERSION_HEADER};
+use reqwest::header::{HeaderMap, HeaderValue};
 use reqwest::{IntoUrl, Response};
 use sensitive_url::SensitiveUrl;
 use serde::de::DeserializeOwned;
@@ -108,13 +109,20 @@ impl BuilderHttpClient {
         &self,
         url: U,
         body: &T,
+        headers: HeaderMap,
         timeout: Option<Duration>,
     ) -> Result<Response, Error> {
         let mut builder = self.client.post(url);
         if let Some(timeout) = timeout {
             builder = builder.timeout(timeout);
         }
-        let response = builder.json(body).send().await.map_err(Error::from)?;
+
+        let response = builder
+            .headers(headers)
+            .json(body)
+            .send()
+            .await
+            .map_err(Error::from)?;
         ok_or_error(response).await
     }
 
@@ -151,10 +159,16 @@ impl BuilderHttpClient {
             .push("builder")
             .push("blinded_blocks");
 
+        let mut headers = HeaderMap::new();
+        if let Ok(value) = HeaderValue::from_str(&blinded_block.fork_name_unchecked().to_string()) {
+            headers.insert(CONSENSUS_VERSION_HEADER, value);
+        }
+
         Ok(self
             .post_with_raw_response(
                 path,
                 &blinded_block,
+                headers,
                 Some(self.timeouts.post_blinded_blocks),
             )
             .await?