build(deps): bump github.com/spf13/viper in /frontend (#62)

Bumps [github.com/spf13/viper](https://github.com/spf13/viper) from 1.12.0 to 1.13.0.
- [Release notes](https://github.com/spf13/viper/releases)
- [Commits](https://github.com/spf13/viper/compare/v1.12.0...v1.13.0)

---
updated-dependencies:
- dependency-name: github.com/spf13/viper
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

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

frontend/go.mod

@@ -5,10 +5,7 @@ go 1.16
 require (
 	github.com/felixge/httpsnoop v1.0.3 // indirect
 	github.com/gorilla/handlers v1.5.1
-	github.com/pelletier/go-toml/v2 v2.0.2 // indirect
 	github.com/spf13/pflag v1.0.5
-	github.com/spf13/viper v1.12.0
-	github.com/subosito/gotenv v1.4.0 // indirect
+	github.com/spf13/viper v1.13.0
 	golang.org/x/sys v0.0.0-20220708085239-5a0f0661e09d // indirect
-	gopkg.in/ini.v1 v1.66.6 // indirect
 )