Added empty CRLF for http2 sent headers to avoid skipping missed head…

…ers in debug (#97)

lib/http2/request.js

@@ -87,7 +87,7 @@ class Http2Request extends EventEmitter {
   }
 
   get _header () {
-    return Object.entries(this.stream.sentHeaders)
+    return '\r\n' + Object.entries(this.stream.sentHeaders)
       .map(([key, value]) => `${key}: ${value}`)
       .join('\r\n') + '\r\n\r\n'
   }