Add host header in eBPF HTTP request (#107)

diff --git a/ebpf/accesslog.proto b/ebpf/accesslog.proto
index 8a4e2cc..4155227 100644
--- a/ebpf/accesslog.proto
+++ b/ebpf/accesslog.proto
@@ -177,6 +177,8 @@
     uint64 sizeOfBodyBytes = 4;
     // The trace information if detected.
     AccessLogTraceInfo trace = 5;
+    // The host header of the incoming request.
+    string host = 6;
 }
 
 message AccessLogHTTPProtocolResponse {
@@ -384,4 +386,4 @@
 }
 
 message EBPFAccessLogDownstream {
-}
\ No newline at end of file
+}