build(deps): bump pyinstaller from 6.20.0 to 6.21.0 (#2773)

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](https://github.com/pyinstaller/pyinstaller/compare/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>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

pyinstaller/requirements.txt

@@ -1,5 +1,5 @@
 maigret @ https://github.com/soxoj/maigret/archive/refs/heads/main.zip
 pefile==2023.2.7 # do not bump while pyinstaller is 6.11.1, there is a conflict
 psutil==7.2.2
-pyinstaller==6.20.0
+pyinstaller==6.21.0
 pywin32-ctypes==0.2.3