Bump requests from 2.28.2 to 2.31.0 (#2078)

* Bump requests from 2.28.2 to 2.31.0

Bumps [requests](https://github.com/psf/requests) from 2.28.2 to 2.31.0.
- [Release notes](https://github.com/psf/requests/releases)
- [Changelog](https://github.com/psf/requests/blob/main/HISTORY.md)
- [Commits](https://github.com/psf/requests/compare/v2.28.2...v2.31.0)

---
updated-dependencies:
- dependency-name: requests
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

* Update requests==2.31.0

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: JonnyWong16 <9099342+JonnyWong16@users.noreply.github.com>

[skip ci]

lib/urllib3/filepost.py

@@ -1,28 +1,32 @@
-from __future__ import absolute_import
+from __future__ import annotations
 
 import binascii
 import codecs
 import os
+import typing
 from io import BytesIO
 
-from .fields import RequestField
-from .packages import six
-from .packages.six import b
+from .fields import _TYPE_FIELD_VALUE_TUPLE, RequestField
 
 writer = codecs.lookup("utf-8")[3]
 
+_TYPE_FIELDS_SEQUENCE = typing.Sequence[
+    typing.Union[typing.Tuple[str, _TYPE_FIELD_VALUE_TUPLE], RequestField]
+]
+_TYPE_FIELDS = typing.Union[
+    _TYPE_FIELDS_SEQUENCE,
+    typing.Mapping[str, _TYPE_FIELD_VALUE_TUPLE],
+]
 
-def choose_boundary():
+
+def choose_boundary() -> str:
     """
     Our embarrassingly-simple replacement for mimetools.choose_boundary.
     """
-    boundary = binascii.hexlify(os.urandom(16))
-    if not six.PY2:
-        boundary = boundary.decode("ascii")
-    return boundary
+    return binascii.hexlify(os.urandom(16)).decode()
 
 
-def iter_field_objects(fields):
+def iter_field_objects(fields: _TYPE_FIELDS) -> typing.Iterable[RequestField]:
     """
     Iterate over fields.
 
@@ -30,42 +34,29 @@ def iter_field_objects(fields):
     :class:`~urllib3.fields.RequestField`.
 
     """
-    if isinstance(fields, dict):
-        i = six.iteritems(fields)
-    else:
-        i = iter(fields)
+    iterable: typing.Iterable[RequestField | tuple[str, _TYPE_FIELD_VALUE_TUPLE]]
 
-    for field in i:
+    if isinstance(fields, typing.Mapping):
+        iterable = fields.items()
+    else:
+        iterable = fields
+
+    for field in iterable:
         if isinstance(field, RequestField):
             yield field
         else:
             yield RequestField.from_tuples(*field)
 
 
-def iter_fields(fields):
-    """
-    .. deprecated:: 1.6
-
-    Iterate over fields.
-
-    The addition of :class:`~urllib3.fields.RequestField` makes this function
-    obsolete. Instead, use :func:`iter_field_objects`, which returns
-    :class:`~urllib3.fields.RequestField` objects.
-
-    Supports list of (k, v) tuples and dicts.
-    """
-    if isinstance(fields, dict):
-        return ((k, v) for k, v in six.iteritems(fields))
-
-    return ((k, v) for k, v in fields)
-
-
-def encode_multipart_formdata(fields, boundary=None):
+def encode_multipart_formdata(
+    fields: _TYPE_FIELDS, boundary: str | None = None
+) -> tuple[bytes, str]:
     """
     Encode a dictionary of ``fields`` using the multipart/form-data MIME format.
 
     :param fields:
         Dictionary of fields or list of (key, :class:`~urllib3.fields.RequestField`).
+        Values are processed by :func:`urllib3.fields.RequestField.from_tuples`.
 
     :param boundary:
         If not specified, then a random boundary will be generated using
@@ -76,7 +67,7 @@ def encode_multipart_formdata(fields, boundary=None):
         boundary = choose_boundary()
 
     for field in iter_field_objects(fields):
-        body.write(b("--%s\r\n" % (boundary)))
+        body.write(f"--{boundary}\r\n".encode("latin-1"))
 
         writer(body).write(field.render_headers())
         data = field.data
@@ -84,15 +75,15 @@ def encode_multipart_formdata(fields, boundary=None):
         if isinstance(data, int):
             data = str(data)  # Backwards compatibility
 
-        if isinstance(data, six.text_type):
+        if isinstance(data, str):
             writer(body).write(data)
         else:
             body.write(data)
 
         body.write(b"\r\n")
 
-    body.write(b("--%s--\r\n" % (boundary)))
+    body.write(f"--{boundary}--\r\n".encode("latin-1"))
 
-    content_type = str("multipart/form-data; boundary=%s" % boundary)
+    content_type = f"multipart/form-data; boundary={boundary}"
 
     return body.getvalue(), content_type