fix: use lowercase l2 in context

Author: varun-doshi

src/server.rs

@@ -612,14 +612,14 @@ impl RollupBoostServer {
                 Ok(payload) => {
                     self.probes.set_health(Health::Healthy);
                     tracing::Span::current().record("payload_source", "L2");
-                    counter!("rpc.blocks_created", "source" => "L2").increment(1);
+                    counter!("rpc.blocks_created", "source" => "l2").increment(1);
 
                     let execution_payload = ExecutionPayload::from(payload.clone());
                     info!(
                         message = "returning block",
                         "hash" = %execution_payload.block_hash(),
                         "number" = %execution_payload.block_number(),
-                        context = "L2",
+                        context = "l2",
                         %payload_id,
                     );