fix(deps): update module github.com/spf13/viper to v1.20.1

Author: renovate[bot]

flagd-proxy/go.mod

@@ -12,7 +12,7 @@ require (
 	github.com/open-feature/flagd/core v0.11.2
 	github.com/prometheus/client_golang v1.21.1
 	github.com/spf13/cobra v1.9.1
-	github.com/spf13/viper v1.19.0
+	github.com/spf13/viper v1.20.1
 	go.opentelemetry.io/otel/exporters/prometheus v0.57.0
 	go.opentelemetry.io/otel/metric v1.35.0
 	go.opentelemetry.io/otel/sdk/metric v1.35.0

flagd/go.mod

@@ -18,7 +18,7 @@ require (
 	github.com/rs/xid v1.6.0
 	github.com/spf13/cobra v1.9.1
 	github.com/spf13/pflag v1.0.6
-	github.com/spf13/viper v1.19.0
+	github.com/spf13/viper v1.20.1
 	github.com/stretchr/testify v1.10.0
 	go.opentelemetry.io/otel v1.35.0
 	go.opentelemetry.io/otel/sdk v1.35.0