build(deps): Bump taskcluster from 26.0.1 to 28.0.0 in /tools (#464)

Bumps [taskcluster](https://github.com/taskcluster/taskcluster) from 26.0.1 to 28.0.0.
- [Release notes](https://github.com/taskcluster/taskcluster/releases)
- [Changelog](https://github.com/taskcluster/taskcluster/blob/master/CHANGELOG.md)
- [Commits](taskcluster/taskcluster@v26.0.1...v28.0.0)

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

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Author: dependabot-preview[bot]

tools/requirements.txt

@@ -3,4 +3,4 @@ async-timeout==3.0.1
 logbook==1.5.3
 raven==6.10.0
 structlog==20.1.0
-taskcluster==26.0.1
+taskcluster==28.0.0