chore(deps-dev): bump mypy from 1.1.1 to 1.4.1

This requires an explicit `cast` of `shutil.copyfileobj` to work-around
a typeshed/Mypy issue.

Bumps [mypy](https://github.com/python/mypy) from 1.1.1 to 1.4.1.
- [Commits](python/mypy@v1.1.1...v1.4.1)

---
updated-dependencies:
- dependency-name: mypy
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

See: python/mypy#15031
See: https://github.com/python/mypy/pull/14902/files#diff-363460977156fcfda748f21565484fe1d5862edf2823e9784cbf34d1e52ff2f2
See: python/mypy#14975

Signed-off-by: dependabot[bot] <support@github.com>
Signed-off-by: Nicolas Trangez <ikke@nicolast.be>

pyproject.toml

@@ -55,7 +55,7 @@ python = "^3.7.15"
 importlib-metadata = {version = ">=3.7.3,<5.0.0", python = "< 3.8"}
 
 [tool.poetry.dev-dependencies]
-mypy = "^1.1"
+mypy = "^1.4"
 flake8 = "^3.9.2"
 flake8-bandit = "^3.0.0"
 flake8-bugbear = "^23.3.12"

tests/conftest.py

@@ -1,10 +1,11 @@
 """Global definitions for pytest tests."""
 
+import io
 import shutil
 import tempfile
 import uuid
 from pathlib import Path
-from typing import Iterator
+from typing import cast, BinaryIO, Callable, Iterator
 
 import pytest
 
@@ -20,6 +21,12 @@ def disk_image(tmp_path: Path) -> Iterator[Path]:
     """Yield the path to a copy of `TESTDATA_DISK`."""
     with tempfile.NamedTemporaryFile(dir=tmp_path) as tmp:
         with open(TESTDATA_DISK, "rb") as disk:
-            shutil.copyfileobj(disk, tmp)
+            copyfileobj = cast(
+                Callable[
+                    [io.BufferedReader, tempfile._TemporaryFileWrapper[bytes]], None
+                ],
+                shutil.copyfileobj,
+            )
+            copyfileobj(disk, tmp)
 
         yield Path(tmp.name)