Gruntfile.js: add LICENSE.md to zip tarball (#2386)
Gruntfile.js: add LICENSE.md to zip tarball (#2386)

Fix #2385

Signed-off-by: Fabrice Fontaine <7d88633730b8b85c1516e612893df72eae9cd341@gmail.com>
jquery-validation/jquery-validation,jquery-validation/jquery-validation