chore(deps): bump github.com/go-viper/mapstructure/v2

Bumps [github.com/go-viper/mapstructure/v2](https://github.com/go-viper/mapstructure) from 2.0.0-alpha.1 to 2.4.0.
- [Release notes](https://github.com/go-viper/mapstructure/releases)
- [Changelog](https://github.com/go-viper/mapstructure/blob/main/CHANGELOG.md)
- [Commits](https://github.com/go-viper/mapstructure/compare/v2.0.0-alpha.1...v2.4.0)

---
updated-dependencies:
- dependency-name: github.com/go-viper/mapstructure/v2
  dependency-version: 2.4.0
  dependency-type: indirect
...

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

go.mod

@@ -7,6 +7,7 @@ require (
 	github.com/coreos/go-oidc/v3 v3.11.0
 	github.com/disintegration/imaging v1.6.2
 	github.com/emersion/go-imap/v2 v2.0.0-beta.3
+	github.com/emersion/go-message v0.18.1
 	github.com/fasthttp/websocket v1.5.9
 	github.com/ferluci/fast-realip v1.0.1
 	github.com/google/uuid v1.6.0
@@ -49,12 +50,11 @@ require (
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
-	github.com/emersion/go-message v0.18.1 // indirect
 	github.com/emersion/go-sasl v0.0.0-20231106173351-e73c9f7bad43 // indirect
 	github.com/fasthttp/router v1.5.0 // indirect
 	github.com/fsnotify/fsnotify v1.6.0 // indirect
 	github.com/go-jose/go-jose/v4 v4.0.5 // indirect
-	github.com/go-viper/mapstructure/v2 v2.0.0-alpha.1 // indirect
+	github.com/go-viper/mapstructure/v2 v2.4.0 // indirect
 	github.com/gogs/chardet v0.0.0-20211120154057-b7413eaefb8f // indirect
 	github.com/jaytaylor/html2text v0.0.0-20230321000545-74c2419ad056 // indirect
 	github.com/klauspost/compress v1.18.0 // indirect