fix angular vulnerabilities

added 1096 packages from 1283 contributors and audited 21689 packages in 252.426s
found 14 vulnerabilities (9 low, 5 high)
  run `npm audit fix` to fix them, or `npm audit` for details
"git" no se reconoce como un comando interno o externo,
programa o archivo por lotes ejecutable.

run     $ npm i karma@3.0.0 --save

https://angular.io/guide/rx-library