Angular 9 with original ng2-completer?

Hi

I was wondering if you could be persuaded to release a patch to version 1.6.0 with the fixed reference to ng2-completer, but without upgrading to Angular 10.

For context, we have a transitive dependency to the ng2-completer which means we need to reference the "real" version, but for some reason with both that and @akveo/ng2-completer in our package.json the prod aot compilation fails at the very end with:

```
ERROR in ./node_modules/ng2-smart-table/ng2-smart-table.ngfactory.js
Module not found: Error: Can't resolve '../@akveo/ng2-completer/ng2-completer.ngfactory' in 'C:\[code_path]\node_modules\ng2-smart-table'
```

@yggg I know this project is in low maintenance, but I wonder if this might be possible. I'm happy to put a PR together to do this, but obviously will need you to do the merging/building.