lessc runs with "/usr/bin/env node"

The `/usr/bin/lessc` executable installed by the node-less package has a shbang of `#!/usr/bin/env node`. This causes it to pick up on any `node` executable that is earlier on PATH. In my case that's one installed by nvm that doesn't look for packages in the `/usr/share/nodejs` directory that contains the dependencies of `lessc`, such as `tslib`. This results in a traceback like:

```
❯ lessc
internal/modules/cjs/loader.js:797
    throw err;
    ^

Error: Cannot find module 'tslib'
Require stack:
- /usr/share/nodejs/less/lib/less/utils.js
- /usr/share/nodejs/less/bin/lessc
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:794:15)
    at Function.Module._load (internal/modules/cjs/loader.js:687:27)
    at Module.require (internal/modules/cjs/loader.js:849:19)
    at require (internal/modules/cjs/helpers.js:74:18)
    at Object.<anonymous> (/usr/share/nodejs/less/lib/less/utils.js:3:15)
    at Module._compile (internal/modules/cjs/loader.js:956:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:973:10)
    at Module.load (internal/modules/cjs/loader.js:812:32)
    at Function.Module._load (internal/modules/cjs/loader.js:724:14)
    at Module.require (internal/modules/cjs/loader.js:849:19) {
  code: 'MODULE_NOT_FOUND',
  requireStack: [
    '/usr/share/nodejs/less/lib/less/utils.js',
    '/usr/share/nodejs/less/bin/lessc'
  ]
}
```

Proposed solution: `lessc` should have a shbang of `#!/usr/bin/node` so that it runs with a `node` that looks for the packaged dependencies.

Workaround: Use `/usr/bin/node /usr/bin/lessc` instead of running `lessc` directly.