Bump mypy

Also, warn_unused_configs requires turning off incremental mode using incremental = False.
https://mypy.readthedocs.io/en/stable/config_file.html#confval-warn_unused_configs

Author: DimitriPapadopoulos

ci-constraints-requirements.txt

@@ -87,9 +87,7 @@ markupsafe==2.1.5 ; python_full_version < '3.9'
     # via jinja2
 markupsafe==3.0.2 ; python_full_version >= '3.9'
     # via jinja2
-mypy==1.14.1 ; python_full_version < '3.9'
-    # via cryptography (pyproject.toml)
-mypy==1.15.0 ; python_full_version >= '3.9'
+mypy==1.15.0
     # via cryptography (pyproject.toml)
 mypy-extensions==1.1.0
     # via mypy

pyproject.toml

@@ -87,7 +87,7 @@ sdist = ["build >=1.0.0"]
 # `click` included because its needed to type check `release.py`
 pep8test = [
     "ruff >=0.3.6",
-    "mypy >=1.4",
+    "mypy >=1.15",
     "check-sdist",
     "click >=8.0.1",
 ]

src/cryptography/utils.py

@@ -32,10 +32,7 @@ class CryptographyDeprecationWarning(UserWarning):
 # be more accurately named: Bufferable. It means something which has an
 # `__buffer__`. Which means you can't actually treat the result as a buffer
 # (and do things like take a `len()`).
-if sys.version_info >= (3, 9):
-    Buffer = typing.Union[bytes, bytearray, memoryview]
-else:
-    Buffer = typing.ByteString
+Buffer = typing.Union[bytes, bytearray, memoryview]
 
 
 def _check_bytes(name: str, value: bytes) -> None: