Bump filelock from 3.16.1 to 3.20.1

Bumps [filelock](https://github.com/tox-dev/py-filelock) from 3.16.1 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@3.16.1...3.20.1)

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

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

Author: dependabot[bot]

requirements_dev.txt

@@ -28,7 +28,7 @@ distlib==0.3.9
     # via virtualenv
 executing==2.1.0
     # via stack-data
-filelock==3.16.1
+filelock==3.20.1
     # via
     #   tox
     #   virtualenv