feat: add kustomize

- add kustomize to rpmbuilder

rpms/kustomize/resources/build.sh

@@ -0,0 +1,14 @@
+#!/usr/bin/bash
+set -e
+
+# Download kustomize binary
+wget -O /app/kustomize_v${PACKAGE_VERSION}_linux_amd64.tar.gz https://artifactapi.k8s.syd1.au.unkin.net/api/v1/remote/github/kubernetes-sigs/kustomize/releases/download/kustomize%2Fv${PACKAGE_VERSION}/kustomize_v${PACKAGE_VERSION}_linux_amd64.tar.gz
+
+# Extract the binary
+tar -xzf /app/kustomize_v${PACKAGE_VERSION}_linux_amd64.tar.gz -C /app/
+
+# Process nfpm.yaml with envsubst
+envsubst < /app/resources/nfpm.yaml > /app/nfpm.yaml
+
+# Build the RPM
+nfpm pkg --config /app/nfpm.yaml --target /app/dist --packager rpm