fix: remove null parameter signatures for tap

[9renpoto]

closes #180

import { of } from 'rxjs';
import { tap } from 'rxjs/operators';

const source = of(3, 2, 1);

source.pipe(
  // Deprecated
  tap(null, null, () => console.log('Complete. Cookie time.'))
).subscribe(...);

source.pipe(
  // Recommended
  tap({
    complete: () => console.log('Complete. Cookie time.')
  })
).subscribe(...);

refs: https://dzhavat.github.io/2019/02/17/deprecations-in-rxjs-v6-4-0.html

[coveralls]

Pull Request Test Coverage Report for Build 615237756

• 9 of 13 (69.23%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.2%) to 87.963%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
lib/raven.interceptor.ts	9	13	69.23%

Totals
Change from base Build 609461535:	0.2%
Covered Lines:	61
Relevant Lines:	66

---

💛 - Coveralls

[9renpoto]

@kayvaninvemo can you review it ? thank you :)

[karianpour]

It matches the RxJs new interface

[mentos1386]

LGTM! Thanks for all the work you do @9renpoto!