build(deps): bump pyinstaller from 6.20.0 to 6.21.0

Bumps [pyinstaller](https://github.com/pyinstaller/pyinstaller) from 6.20.0 to 6.21.0.
- [Release notes](https://github.com/pyinstaller/pyinstaller/releases)
- [Changelog](https://github.com/pyinstaller/pyinstaller/blob/develop/doc/CHANGES.rst)
- [Commits](pyinstaller/pyinstaller@v6.20.0...v6.21.0)

---
updated-dependencies:
- dependency-name: pyinstaller
  dependency-version: 6.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

pyproject.toml

@@ -27,7 +27,7 @@ python-cli-template = "python_cli_template.cli:main"
 [project.optional-dependencies]
 build = [
     "build==1.5.0",
-    "pyinstaller==6.20.0",
+    "pyinstaller==6.21.0",
     "twine==6.2.0",
 ]
 docs = [