security/ruby-rex-powershell: update to 0.1.89

0.1.89 (2021-01-19)

* Land #25, Update gempsec
* Add in support for -version flag using @wo4haoren's original
  contributions from #24 with some tweaks

0.1.88 (2020-11-30)

* Land #14, Add option to use Invoke-Expression and RC4
* relax dev bundle and update authors …
- Allows bundle with latest bundler
- Updates authors to reflect current maintainers
- Update travis to test with 2.7.2

(taca)