Updated README.md.

Author: synchronizing

README.md

@@ -44,15 +44,19 @@ req = httpq.Request(
     method="GET",
     target="/get",
     protocol="HTTP/1.1",
-    headers={"Host": "httpbin.org", "Content-Length": 12},
+    headers={
+        "Host": "httpbin.org",
+        "Content-Length": 12,
+        "Accept": ["Accept: application/json", "Accept: text/plain"],
+    },
     body="Hello world!",
 )
 
 resp = httpq.Response(
     protocol="HTTP/1.1",
     status=200,
     reason="OK",
-    headers={"Content-Length": 12},
+    headers={"Content-Length": 12, "Content-Type": "text/plain"},
     body="Hello world!",
 )
 ```
@@ -64,13 +68,16 @@ req = httpq.Request.parse(
     b"GET /get HTTP/1.1\r\n"
     b"Host: httpbin.org\r\n"
     b"Content-Length: 12\r\n"
+    b"Accept: application/json\r\n"
+    b"Accept: text/plain\r\n"
     b"\r\n"
     b"Hello world!"
 )
 
 resp = httpq.Response.parse(
     b"HTTP/1.1 200 OK\r\n"
     b"Content-Length: 12\r\n"
+    b"Content-Type: text/plain\r\n"
     b"\r\n"
     b"Hello world!"
 )
@@ -83,12 +90,15 @@ req = httpq.Request()
 req.feed(b"GET /get HTTP/1.1\r\n")
 req.feed(b"Host: httpbin.org\r\n")
 req.feed(b"Content-Length: 18\r\n")
+req.feed(b"Accept: application/json\r\n")
+req.feed(b"Accept: text/plain\r\n")
 req.feed(b"\r\n")
 req.feed(b"Hello world!")
 
 resp = httpq.Response()
 resp.feed(b"HTTP/1.1 200 OK\r\n")
 resp.feed(b"Content-Length: 12\r\n")
+resp.feed(b"Content-Type: text/plain\r\n")
 resp.feed(b"\r\n")
 resp.feed(b"Hello world!")
 ```