Bump watchdog from 0.9.0 to 4.0.0 (#2544)

Bumps [watchdog](https://github.com/gorakhargosh/watchdog) from 0.9.0 to 4.0.0.
- [Release notes](https://github.com/gorakhargosh/watchdog/releases)
- [Changelog](https://github.com/gorakhargosh/watchdog/blob/master/changelog.rst)
- [Commits](gorakhargosh/watchdog@v0.9.0...v4.0.0)

---
updated-dependencies:
- dependency-name: watchdog
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

dev-requirements.txt

@@ -6,7 +6,7 @@ pep8
 pyflakes
 pydocstyle<7.0
 httmock==1.4.0
-watchdog==0.9.0
+watchdog==4.0.0
 wooper==0.4.4
 requests-mock==1.11.0
 responses