chore: update Dockerfile to use Go version 1.21

- Update the value of the `GO_VERSION` argument in the Dockerfile from `1.20` to `1.21`

Signed-off-by: Bo-Yi Wu <[email protected]>

Author: appleboy

Dockerfile.06

@@ -1,5 +1,5 @@
 # syntax=docker/dockerfile:1
-ARG GO_VERSION=1.20
+ARG GO_VERSION=1.21
 FROM golang:${GO_VERSION}-alpine as builder
 
 WORKDIR /src