hack(generated-files): bump golang image to bookworm

#7 [internal] load metadata for docker.io/library/golang:1.20.6-buster
#7 ERROR: docker.io/library/golang:1.20.6-buster: not found

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>
(cherry picked from commit 1123bfed10)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

hack/dockerfiles/generated-files.Dockerfile

@@ -9,7 +9,7 @@ ARG GO_VERSION="1.20.6"
 ARG PROTOC_VERSION="3.11.4"
 
 # protoc is dynamically linked to glibc so can't use alpine base
-FROM golang:${GO_VERSION}-buster AS base
+FROM golang:${GO_VERSION}-bookworm AS base
 RUN apt-get update && apt-get --no-install-recommends install -y git unzip
 ARG PROTOC_VERSION
 ARG TARGETOS