Add exe extension to Windows release binary (#2022)

This fix adds exe extension to Windows release binary.

This fix fixes 2021.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

Makefile.release

@@ -70,7 +70,7 @@ build:
 	@echo Building: darwin/amd64 - $(VERSION)
 	mkdir -p build/darwin/amd64 && $(MAKE) coredns BINARY=build/darwin/amd64/$(NAME) SYSTEM="GOOS=darwin GOARCH=amd64" CHECKS="godeps" VERBOSE=""
 	@echo Building: windows/amd64 - $(VERSION)
-	mkdir -p build/windows/amd64 && $(MAKE) coredns BINARY=build/windows/amd64/$(NAME) SYSTEM="GOOS=windows GOARCH=amd64" CHECKS="" VERBOSE=""
+	mkdir -p build/windows/amd64 && $(MAKE) coredns BINARY=build/windows/amd64/$(NAME).exe SYSTEM="GOOS=windows GOARCH=amd64" CHECKS="" VERBOSE=""
 	@echo Building: linux/$(LINUX_ARCH) - $(VERSION) ;\
 	for arch in $(LINUX_ARCH); do \
 	    mkdir -p build/linux/$$arch  && $(MAKE) coredns BINARY=build/linux/$$arch/$(NAME) SYSTEM="GOOS=linux GOARCH=$$arch" CHECKS="" VERBOSE="" ;\
@@ -81,7 +81,7 @@ tar:
 	@echo Cleaning old releases
 	@rm -rf release && mkdir release
 	tar -zcf release/$(NAME)_$(VERSION)_darwin_amd64.tgz -C build/darwin/amd64 $(NAME)
-	tar -zcf release/$(NAME)_$(VERSION)_windows_amd64.tgz -C build/windows/amd64 $(NAME)
+	tar -zcf release/$(NAME)_$(VERSION)_windows_amd64.tgz -C build/windows/amd64 $(NAME).exe
 	for arch in $(LINUX_ARCH); do \
 	    tar -zcf release/$(NAME)_$(VERSION)_linux_$$arch.tgz -C build/linux/$$arch $(NAME) ;\
 	done