Bump github.com/spf13/viper from 1.7.1 to 1.15.0 (#195)

Bumps [github.com/spf13/viper](https://github.com/spf13/viper) from 1.7.1 to 1.15.0.
- [Release notes](https://github.com/spf13/viper/releases)
- [Commits](spf13/viper@v1.7.1...v1.15.0)

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

go.mod

@@ -6,7 +6,6 @@ require (
 	github.com/aws/aws-sdk-go v1.44.192
 	github.com/mitchellh/go-homedir v1.1.0
 	github.com/spf13/cobra v1.6.1
-	github.com/spf13/viper v1.7.1
+	github.com/spf13/viper v1.15.0
 	github.com/stretchr/testify v1.8.1
-	gopkg.in/yaml.v2 v2.4.0 // indirect
 )