Bump github.com/spf13/viper from 1.20.1 to 1.21.0 (#28)

Bumps [github.com/spf13/viper](https://github.com/spf13/viper) from 1.20.1 to 1.21.0.
- [Release notes](https://github.com/spf13/viper/releases)
- [Commits](https://github.com/spf13/viper/compare/v1.20.1...v1.21.0)

---
updated-dependencies:
- dependency-name: github.com/spf13/viper
  dependency-version: 1.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

go.mod

@@ -4,22 +4,21 @@ go 1.24.2
 
 require (
 	github.com/gorilla/feeds v1.2.0
-	github.com/spf13/viper v1.20.1
+	github.com/spf13/viper v1.21.0
 	github.com/tcolgate/mp3 v0.0.0-20170426193717-e79c5a46d300
 )
 
 require (
 	github.com/fsnotify/fsnotify v1.9.0 // indirect
 	github.com/go-viper/mapstructure/v2 v2.4.0 // indirect
-	github.com/pelletier/go-toml/v2 v2.2.3 // indirect
-	github.com/sagikazarmark/locafero v0.9.0 // indirect
-	github.com/sourcegraph/conc v0.3.0 // indirect
-	github.com/spf13/afero v1.14.0 // indirect
-	github.com/spf13/cast v1.7.1 // indirect
-	github.com/spf13/pflag v1.0.6 // indirect
+	github.com/pelletier/go-toml/v2 v2.2.4 // indirect
+	github.com/sagikazarmark/locafero v0.11.0 // indirect
+	github.com/sourcegraph/conc v0.3.1-0.20240121214520-5f936abd7ae8 // indirect
+	github.com/spf13/afero v1.15.0 // indirect
+	github.com/spf13/cast v1.10.0 // indirect
+	github.com/spf13/pflag v1.0.10 // indirect
 	github.com/subosito/gotenv v1.6.0 // indirect
-	go.uber.org/multierr v1.11.0 // indirect
+	go.yaml.in/yaml/v3 v3.0.4 // indirect
 	golang.org/x/sys v0.32.0 // indirect
-	golang.org/x/text v0.24.0 // indirect
-	gopkg.in/yaml.v3 v3.0.1 // indirect
+	golang.org/x/text v0.28.0 // indirect
 )