Update module github.com/sirupsen/logrus to v1.8.1

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
github.com/sirupsen/logrus	require	minor	v1.7.0 -> v1.8.1

---

Release Notes

sirupsen/logrus

### [`v1.8.1`](https://togithub.com/sirupsen/logrus/compare/v1.8.0...v1.8.1) [Compare Source](https://togithub.com/sirupsen/logrus/compare/v1.8.0...v1.8.1) ### [`v1.8.0`](https://togithub.com/sirupsen/logrus/releases/tag/v1.8.0) [Compare Source](https://togithub.com/sirupsen/logrus/compare/v1.7.1...v1.8.0) Correct versioning number replacing v1.7.1 ### [`v1.7.1`](https://togithub.com/sirupsen/logrus/releases/tag/v1.7.1) [Compare Source](https://togithub.com/sirupsen/logrus/compare/v1.7.0...v1.7.1) ### Code quality: - use go 1.15 in travis - use magefile as task runner ### Fixes: - small fixes about new go 1.13 error formatting system - Fix for long time race condiction with mutating data hooks ### Features: - build support for zos

---

Configuration

📅 Schedule: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

---

• [ ] If you want to rebase/retry this PR, click this checkbox.

---

This PR has been generated by Mend Renovate. View repository job log here.