Run hack generate tool directly (#1118)

Co-authored-by: Christoph Stäbler <cstabler@redhat.com>

openshift/generate.sh

@@ -4,16 +4,7 @@ set -euo pipefail
 
 repo_root_dir=$(dirname "$(realpath "${BASH_SOURCE[0]}")")/..
 
-tmp_dir=$(mktemp -d)
-git clone --branch main https://github.com/openshift-knative/hack "$tmp_dir"
-
-pushd "$tmp_dir"
-go install github.com/openshift-knative/hack/cmd/generate
-popd
-
-rm -rf "$tmp_dir"
-
-$(go env GOPATH)/bin/generate \
+GOFLAGS='' go run github.com/openshift-knative/hack/cmd/generate@latest \
   --root-dir "${repo_root_dir}" \
   --generators dockerfile \
   --additional-packages tzdata \