Bump tar, fsevents and gulp-sass in /src/Exceptionless.EmailTemplates

Removes [tar](https://github.com/isaacs/node-tar). It's no longer used after updating ancestor dependencies [tar](https://github.com/isaacs/node-tar), [fsevents](https://github.com/fsevents/fsevents) and [gulp-sass](https://github.com/dlmanning/gulp-sass). These dependencies need to be updated together.


Removes `tar`

Updates `fsevents` from 1.2.12 to 1.2.13
- [Release notes](https://github.com/fsevents/fsevents/releases)
- [Commits](fsevents/fsevents@1.2.12...v1.2.13)

Updates `gulp-sass` from 3.2.1 to 6.0.0
- [Release notes](https://github.com/dlmanning/gulp-sass/releases)
- [Changelog](https://github.com/dlmanning/gulp-sass/blob/master/CHANGELOG.md)
- [Commits](dlmanning/gulp-sass@v3.2.1...v6.0.0)

---
updated-dependencies:
- dependency-name: tar
  dependency-type: indirect
- dependency-name: fsevents
  dependency-type: indirect
- dependency-name: gulp-sass
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]