Update request urllib3 (#464)

* requests: updated to version 2.27.1

* urllib3: updated to version 1.26.18

lib/urllib3/util/__init__.py

@@ -2,23 +2,23 @@ from __future__ import absolute_import
 
 # For backwards compatibility, provide imports that used to be here.
 from .connection import is_connection_dropped
-from .request import make_headers
+from .request import SKIP_HEADER, SKIPPABLE_HEADERS, make_headers
 from .response import is_fp_closed
+from .retry import Retry
 from .ssl_ import (
-    SSLContext,
+    ALPN_PROTOCOLS,
     HAS_SNI,
     IS_PYOPENSSL,
     IS_SECURETRANSPORT,
+    PROTOCOL_TLS,
+    SSLContext,
     assert_fingerprint,
     resolve_cert_reqs,
     resolve_ssl_version,
     ssl_wrap_socket,
-    PROTOCOL_TLS,
 )
-from .timeout import current_time, Timeout
-
-from .retry import Retry
-from .url import get_host, parse_url, split_first, Url
+from .timeout import Timeout, current_time
+from .url import Url, get_host, parse_url, split_first
 from .wait import wait_for_read, wait_for_write
 
 __all__ = (
@@ -27,6 +27,7 @@ __all__ = (
     "IS_SECURETRANSPORT",
     "SSLContext",
     "PROTOCOL_TLS",
+    "ALPN_PROTOCOLS",
     "Retry",
     "Timeout",
     "Url",
@@ -43,4 +44,6 @@ __all__ = (
     "ssl_wrap_socket",
     "wait_for_read",
     "wait_for_write",
+    "SKIP_HEADER",
+    "SKIPPABLE_HEADERS",
 )