downgrade the viper version

Author: kpacha

go.mod

@@ -118,7 +118,7 @@ require (
 	github.com/spf13/cast v1.5.0 // indirect
 	github.com/spf13/jwalterweatherman v1.1.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
-	github.com/spf13/viper v1.13.0 // indirect
+	github.com/spf13/viper v1.12.0 // indirect
 	github.com/subosito/gotenv v1.4.1 // indirect
 	github.com/tmthrgd/atomics v0.0.0-20190904060638-dc7a5fcc7e0d // indirect
 	github.com/tmthrgd/go-bitset v0.0.0-20190904054048-394d9a556c05 // indirect