feat: upgrade to angular 8

[scttcper]

BREAKING CHANGE: requires angular 8

[codecov]

Codecov Report

Merging #699 into master will decrease coverage by 7.34%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #699      +/-   ##
==========================================
- Coverage    62.5%   55.15%   -7.35%     
==========================================
  Files          19       19              
  Lines         608      504     -104     
  Branches       95       92       -3     
==========================================
- Hits          380      278     -102     
- Misses        190      192       +2     
+ Partials       38       34       -4

Impacted Files	Coverage Δ
src/lib/toastr/toast.component.ts	71.42% <ø> (-2.89%)	⬇️
src/app/notyf.toast.ts	100% <ø> (ø)	⬆️
src/lib/toastr/toastr.service.ts	46.8% <100%> (-5.53%)	⬇️
src/lib/portal/portal.ts	52.63% <0%> (-17.37%)	⬇️
src/lib/toastr/toast.directive.ts	50% <0%> (-16.67%)	⬇️
src/lib/overlay/overlay-ref.ts	75% <0%> (-12.5%)	⬇️
src/lib/toastr/toastr.module.ts	57.14% <0%> (-9.53%)	⬇️
src/app/pink.toast.ts	55.55% <0%> (-8.09%)	⬇️
src/app/home/home.component.ts	60.31% <0%> (-7.69%)	⬇️
src/lib/overlay/overlay-container.ts	72.72% <0%> (-7.28%)	⬇️
... and 9 more

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[scttcper]

🎉 This PR is included in version 11.0.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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