Add support for headers to urequest.urlopen

Addition of an optional parameter which allows for the consumer to define headers to pass when making a HTTP request

micropython/urllib.urequest/urllib/urequest.py

@@ -1,7 +1,7 @@
 import socket
 
 
-def urlopen(url, data=None, method="GET"):
+def urlopen(url, data=None, method="GET", headers={}):
     if data is not None and method == "GET":
         method = "POST"
     try:
@@ -40,6 +40,12 @@ def urlopen(url, data=None, method="GET"):
         s.write(host)
         s.write(b"\r\n")
 
+        for k in headers:
+            s.write(k)
+            s.write(b": ")
+            s.write(headers[k])
+            s.write(b"\r\n")
+
         if data:
             s.write(b"Content-Length: ")
             s.write(str(len(data)))