Bump filelock from 3.15.3 to 3.20.1 (#399)

Bumps [filelock](https://github.com/tox-dev/py-filelock) from 3.15.3 to 3.20.1.
- [Release notes](https://github.com/tox-dev/py-filelock/releases)
- [Changelog](https://github.com/tox-dev/filelock/blob/main/docs/changelog.rst)
- [Commits](tox-dev/filelock@3.15.3...3.20.1)

---
updated-dependencies:
- dependency-name: filelock
  dependency-version: 3.20.1
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]