Update try block to check ipv6 or not

Author: RatanShreshtha

src/urllib3/_async/connection.py

@@ -213,9 +213,12 @@ def _build_tunnel_request(host, port, headers):
 
     try:
         socket.inet_pton(socket.AF_INET6, host)
-        target = "[%s]:%d" % (host, port)
     except OSError:
+        # Not a raw IPv6 address
         target = "%s:%d" % (host, port)
+    else:
+        # raw IPv6 address
+        target = "[%s]:%d" % (host, port)
 
     if not isinstance(target, bytes):
         target = target.encode('latin1')