Import errors with RxJS 7

[lobo78]

The latest version of backoff-rxjs (7.0.0) is supposed to support RxJS 7. Howver, when upgrading to RxJS 7.0.1, I see the following build errors:

./node_modules/backoff-rxjs/dist/esm2015/observable/intervalBackoff.js:14:31-37 - Error: export 'expand' (imported as '
expand') was not found in 'rxjs'                                                                                          
./node_modules/backoff-rxjs/dist/esm2015/observable/intervalBackoff.js:15:87-92 - Error: export 'mapTo' (imported as 'm
apTo') was not found in 'rxjs'                               
./node_modules/backoff-rxjs/dist/esm2015/operators/retryBackoff.js:21:11-16 - Error: export 'defer' (imported as 'defer
') was not found in 'rxjs'                                    
./node_modules/backoff-rxjs/dist/esm2015/operators/retryBackoff.js:26:17-20 - Error: export 'iif' (imported as 'iif') w
as not found in 'rxjs'
./node_modules/backoff-rxjs/dist/esm2015/operators/retryBackoff.js:28:13-18 - Error: export 'timer' (imported as 'timer
') was not found in 'rxjs'
./node_modules/backoff-rxjs/dist/esm2015/operators/retryBackoff.js:28:83-93 - Error: export 'throwError' (imported as '
throwError') was not found in 'rxjs'

It seems that in RxJS 7, the above operators must be imported from rxjs/operators rather than rxjs.