Bump filelock from 3.19.1 to 3.20.1 (#280)

Bumps [filelock](https://github.com/tox-dev/py-filelock) from 3.19.1 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@3.19.1...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]

dev-requirements.txt

@@ -10,7 +10,7 @@ distlib==0.4.0
     # via virtualenv
 docutils==0.22.3
     # via readme-renderer
-filelock==3.19.1
+filelock==3.20.1
     # via
     #   tox
     #   virtualenv