adds macOS (arm64) plugin build (#177)

Co-authored-by: Paul S. Schweigert <[email protected]>

Author: knative-prow-robot

hack/release.sh

@@ -37,6 +37,8 @@ function build_release() {
   GOOS=linux GOARCH=arm64 go build -mod=vendor -ldflags "${ld_flags}" -o ./${PLUGIN}-linux-arm64 ./cmd/...
   echo "🚧 🍏 Building for macOS"
   GOOS=darwin GOARCH=amd64 go build -mod=vendor -ldflags "${ld_flags}" -o ./${PLUGIN}-darwin-amd64 ./cmd/...
+  echo "🚧 🍎 Building for macOS (arm64)"
+  GOOS=darwin GOARCH=arm64 go build -mod=vendor -ldflags "${ld_flags}" -o ./${PLUGIN}-darwin-arm64 ./cmd/...
   echo "🚧 🎠 Building for Windows"
   GOOS=windows GOARCH=amd64 go build -mod=vendor -ldflags "${ld_flags}" -o ./${PLUGIN}-windows-amd64.exe ./cmd/...
   echo "🚧 Z  Building for Linux(s390x)"