[BUG] Error with Angular 10 and ExcelJS 4.1.1

## 🐛 Bug Report
Error on compilation with Angular 10
"export 'Workbook' (imported as 'ExcelJS') was not found in 'exceljs'

Lib version: 4.1.1

## Steps To Reproduce
```javascript
const workbook = new ExcelJS.Workbook();
const worksheet = workbook.addWorksheet('Main sheet');
```
Run command ng build and error occured
## The expected behaviour:

Angular compilation will be success