fix(deps): update python demos

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence	Type	Update	New value	References	Sourcegraph
black (changelog)	>=25.9.0 → >=25.12.0			project.optional-dependencies	minor	>=25.12.0	source, changelog
python (source)	>=3.14.0 → >=3.14.2			requires-python	patch	>=3.14.2	homepage, source
python	3.14.0 → 3.14.2				patch	3.14.2	source
python-dotenv	>=1.1.1,<1.2 → >=1.2.1,<1.3			project.dependencies	minor	>=1.2.1,<1.3	source

Test plan: CI should pass with updated dependencies. No review required: this is an automated dependency update PR.

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Release Notes

psf/black (black)

v25.12.0

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Highlights

• Black no longer supports running with Python 3.9 (#​4842)

Stable style

• Fix bug where comments preceding # fmt: off/# fmt: on blocks were incorrectly
  removed, particularly affecting Jupytext's # %% [markdown] comments (#​4845)
• Fix crash when multiple # fmt: skip comments are used in a multi-part if-clause, on
  string literals, or on dictionary entries with long lines (#​4872)
• Fix possible crash when fmt: directives aren't on the top level (#​4856)

Preview style

• Fix fmt: skip skipping the line after instead of the line it's on (#​4855)
• Remove unnecessary parentheses from the left-hand side of assignments while preserving
  magic trailing commas and intentional multiline formatting (#​4865)
• Fix fix_fmt_skip_in_one_liners crashing on with statements (#​4853)
• Fix fix_fmt_skip_in_one_liners crashing on annotated parameters (#​4854)
• Fix new lines being added after imports with # fmt: skip on them (#​4894)

Packaging

• Releases now include arm64 Windows binaries and wheels (#​4814)

Integrations

• Add output-file input to GitHub Action psf/black to write formatter output to a
  file for artifact capture and log cleanliness (#​4824)

v25.11.0

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Highlights

• Enable base 3.14 support (#​4804)
• Add support for the new Python 3.14 t-string syntax introduced by PEP 750 (#​4805)

Stable style

• Fix bug where comments between # fmt: off and # fmt: on were reformatted (#​4811)
• Comments containing fmt directives now preserve their exact formatting instead of
  being normalized (#​4811)

Preview style

• Move multiline_string_handling from --unstable to --preview (#​4760)
• Fix bug where module docstrings would be treated as normal strings if preceded by
  comments (#​4764)
• Fix bug where python 3.12 generics syntax split line happens weirdly (#​4777)
• Standardize type comments to form # type: <value> (#​4645)
• Fix fix_fmt_skip_in_one_liners preview feature to respect # fmt: skip for compound
  statements with semicolon-separated bodies (#​4800)

Configuration

• Add no_cache option to control caching behavior. (#​4803)

Packaging

• Releases now include arm64 Linux binaries (#​4773)

Output

• Write unchanged content to stdout when excluding formatting from stdin using pipes
  (#​4610)

Blackd

• Implemented BlackDClient. This simple python client allows to easily send formatting
  requests to blackd (#​4774)

Integrations

• Enable 3.14 base CI (#​4804)
• Enhance GitHub Action psf/black to support the required-version major-version-only
  "stability" format when using pyproject.toml (#​4770)
• Improve error message for vim plugin users. It now handles independently vim version
• Vim: Warn on unsupported Vim and Python versions independently (#​4772)
• Vim: Print the import paths when importing black fails (#​4675)
• Vim: Fix handling of virtualenvs that have a different Python version (#​4675)

python/cpython (python)

v3.14.2

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v3.14.1

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theskumar/python-dotenv (python-dotenv)

v1.2.1

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• Move more config to pyproject.toml, removed setup.cfg
• Add support for reading .env from FIFOs (Unix) by [@​sidharth-sudhir] in [#​586]

v1.2.0

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• Upgrade build system to use PEP 517 & PEP 518 to use build and pyproject.toml by [@​EpicWink] in [#​583]
• Add support for Python 3.14 by [@​23f3001135] in #​579
• Add support for disabling of load_dotenv() using PYTHON_DOTENV_DISABLED env var. by [@​matthewfranglen] in [#​569]

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