Add macOS arm64 binary as part of the release (coredns#5721)

Makefile.release

@@ -64,6 +64,8 @@ build:
 	@rm -rf build && mkdir build
 	@echo Building: darwin/amd64 - $(VERSION)
 	mkdir -p build/darwin/amd64 && $(MAKE) coredns BINARY=build/darwin/amd64/$(NAME) SYSTEM="GOOS=darwin GOARCH=amd64" CHECKS="" BUILDOPTS=""
+	@echo Building: darwin/arm64 - $(VERSION)
+	mkdir -p build/darwin/arm64 && $(MAKE) coredns BINARY=build/darwin/arm64/$(NAME) SYSTEM="GOOS=darwin GOARCH=arm64" CHECKS="" BUILDOPTS=""
 	@echo Building: windows/amd64 - $(VERSION)
 	mkdir -p build/windows/amd64 && $(MAKE) coredns BINARY=build/windows/amd64/$(NAME).exe SYSTEM="GOOS=windows GOARCH=amd64" CHECKS="" BUILDOPTS=""
 	@echo Building: linux/$(LINUX_ARCH) - $(VERSION) ;\
@@ -76,6 +78,7 @@ tar:
 	@echo Cleaning old releases
 	@rm -rf release && mkdir release
 	tar -zcf release/$(NAME)_$(VERSION)_darwin_amd64.tgz -C build/darwin/amd64 $(NAME)
+	tar -zcf release/$(NAME)_$(VERSION)_darwin_arm64.tgz -C build/darwin/arm64 $(NAME)
 	tar -zcf release/$(NAME)_$(VERSION)_windows_amd64.tgz -C build/windows/amd64 $(NAME).exe
 	for arch in $(LINUX_ARCH); do \
 	    tar -zcf release/$(NAME)_$(VERSION)_linux_$$arch.tgz -C build/linux/$$arch $(NAME) ;\