Update .npmignore

```
% tar -tvf unorm-1.3.2.tgz
-rw-r--r--  0 502    20        831 Mar 10 17:30 package/package.json
-rw-r--r--  0 502    20       4334 Mar 10 17:30 package/README.md
-rw-r--r--  0 502    20       2198 Oct  3 08:15 package/LICENSE.md
-rw-r--r--  0 502    20     141692 Mar 10 18:31 package/lib/unorm.js
```