Update filelock requirement from ~=3.4 to ~=3.15

Updates the requirements on [filelock](https://github.com/tox-dev/py-filelock) to permit the latest version.
- [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@3.4.0...3.15.4)

---
updated-dependencies:
- dependency-name: filelock
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements-tests.txt

@@ -7,4 +7,4 @@ pytest >= 6.2.0
 requests >= 2.25.1
 pytest-cov
 pytest-timeout
-filelock~=3.4
+filelock~=3.15