Update go to 1.21

Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.19-alpine as builder
+FROM golang:1.21-alpine as builder
 
 RUN apk add --no-cache ca-certificates git
 

go.mod

@@ -1,19 +1,19 @@
 module github.com/IBM-Cloud/redli
 
-go 1.19
+go 1.21
 
 require (
-	github.com/gomodule/redigo v1.8.8
-	github.com/mattn/go-isatty v0.0.14
+	github.com/gomodule/redigo v1.9.2
+	github.com/mattn/go-isatty v0.0.20
 	github.com/mattn/go-shellwords v1.0.12
 	github.com/peterh/liner v1.2.2
 	gopkg.in/alecthomas/kingpin.v2 v2.2.6
 )
 
 require (
 	github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751 // indirect
-	github.com/alecthomas/units v0.0.0-20211218093645-b94a6e3cc137 // indirect
-	github.com/mattn/go-runewidth v0.0.13 // indirect
-	github.com/rivo/uniseg v0.2.0 // indirect
-	golang.org/x/sys v0.0.0-20220412211240-33da011f77ad // indirect
+	github.com/alecthomas/units v0.0.0-20240927000941-0f3dac36c52b // indirect
+	github.com/mattn/go-runewidth v0.0.16 // indirect
+	github.com/rivo/uniseg v0.4.7 // indirect
+	golang.org/x/sys v0.27.0 // indirect
 )