Bump golang.org/x/sync from 0.4.0 to 0.6.0

Bumps [golang.org/x/sync](https://github.com/golang/sync) from 0.4.0 to 0.6.0.
- [Commits](golang/sync@v0.4.0...v0.6.0)

---
updated-dependencies:
- dependency-name: golang.org/x/sync
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

go.mod

@@ -8,7 +8,7 @@ require (
 	github.com/iris-contrib/go.uuid v2.0.0+incompatible
 	github.com/mediocregopher/radix/v3 v3.8.1
 	github.com/nats-io/nats.go v1.31.0
-	golang.org/x/sync v0.4.0
+	golang.org/x/sync v0.6.0
 )
 
 require (