chore(deps): bump github.com/zeromicro/go-zero in /router/mux (#274)

Bumps [github.com/zeromicro/go-zero](https://github.com/zeromicro/go-zero) from 1.5.4 to 1.5.6.
- [Release notes](https://github.com/zeromicro/go-zero/releases)
- [Commits](zeromicro/go-zero@v1.5.4...v1.5.6)

---
updated-dependencies:
- dependency-name: github.com/zeromicro/go-zero
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

router/mux/go.mod

@@ -5,5 +5,5 @@ go 1.15
 require (
 	github.com/gorilla/mux v1.8.0
 	github.com/stretchr/testify v1.8.4
-	github.com/zeromicro/go-zero v1.5.4
+	github.com/zeromicro/go-zero v1.5.6
 )