requests: add annotation for parse_header_links (#8349)

In the requests package the function `utils.parse_header_links()`
takes a str as input and returns a list of dictionaries.

This can be seen in the unit tests that are used:
https://github.com/psf/requests/blob/786255613bd92f87c9c8f066c4271aab1b9eeaad/tests/test_utils.py#L644-L664

stubs/requests/requests/utils.pyi

@@ -44,7 +44,7 @@ def get_environ_proxies(url, no_proxy: Iterable[AnyStr] | None = ...) -> dict[An
 def select_proxy(url: str, proxies: Mapping[Any, Any] | None): ...
 def default_user_agent(name=...): ...
 def default_headers(): ...
-def parse_header_links(value): ...
+def parse_header_links(value: str) -> list[dict[str, str]]: ...
 def guess_json_utf(data): ...
 def prepend_scheme_if_needed(url, new_scheme): ...
 def get_auth_from_url(url): ...