Fix bad variable reference

.gitlab-ci.yml

@@ -18,4 +18,4 @@ package:
     - debuild -us -uc
   artifacts:
     paths:
-      - nginx_${NGINX_VERSION}
+      - nginx_${NGINX_VERSION}*.deb

source/Makefile

 # Relies on latest binary build artifact from https://git.ethitter.com/debian/nginx-build.
 get_binary:
-	curl -o fakeroot/usr/sbin/nginx $NGINX_BINARY
+	curl -o fakeroot/usr/sbin/nginx "${NGINX_BINARY}"
 
 install: get_binary
 	install fakeroot/etc/default/nginx /etc/default/nginx