Bind-mount grunt configs directory to persist changes over time

compose/docker-compose.dev.yml

@@ -11,6 +11,7 @@ services:
       - ./src/composer.lock:/var/www/html/composer.lock:cached
       - ./src/grunt-config.json.sample:/var/www/html/grunt-config.json:cached
       - ./src/Gruntfile.js.sample:/var/www/html/Gruntfile.js:cached
+      - ./src/dev/tools/grunt/configs:/var/www/html/dev/tools/grunt/configs:cached
       - ./src/nginx.conf.sample:/var/www/html/nginx.conf:cached
       - ./src/package.json.sample:/var/www/html/package.json:cached
       #- ./src/auth.json:/var/www/html/auth.json:cached