dockerfile: align go version in vendor dockerfile

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

Author: crazy-max

hack/dockerfiles/vendor.Dockerfile

@@ -16,9 +16,10 @@
 
 # upstream at https://github.com/moby/buildkit/blob/master/hack/dockerfiles/vendor.Dockerfile
 
-ARG GO_VERSION=1.20
+ARG GO_VERSION="1.21"
+ARG ALPINE_VERSION="3.17"
 
-FROM golang:${GO_VERSION}-alpine AS base
+FROM golang:${GO_VERSION}-alpine${ALPINE_VERSION} AS base
 RUN apk add --no-cache git rsync
 WORKDIR /src