chore: add build local script

scripts/build-local.sh

+#!/usr/bin/env bash
+
+set -euo pipefail
+
+pluginDir=".semrel/$(go env GOOS)_$(go env GOARCH)/changelog-generator-default/0.0.0-dev/"
+[[ ! -d "$pluginDir" ]] && {
+  echo "creating $pluginDir"
+  mkdir -p "$pluginDir"
+}
+
+go build -o "$pluginDir/changelog-generator-default" ./cmd/changelog-generator-default