build(deps-dev): bump timecop from 0.9.6 to 0.9.8

Bumps [timecop](https://github.com/travisjeffery/timecop) from 0.9.6 to 0.9.8.
- [Changelog](https://github.com/travisjeffery/timecop/blob/master/History.md)
- [Commits](travisjeffery/timecop@v0.9.6...v0.9.8)

---
updated-dependencies:
- dependency-name: timecop
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

Gemfile.lock

@@ -632,7 +632,7 @@ GEM
     statsd-ruby (1.5.0)
     thor (1.2.2)
     tilt (2.0.11)
-    timecop (0.9.6)
+    timecop (0.9.8)
     timeout (0.4.0)
     tzinfo (2.0.6)
       concurrent-ruby (~> 1.0)