Bump ejs and @microsoft/generator-sharepoint

Bumps [ejs](https://github.com/mde/ejs) to 3.1.10 and updates ancestor dependency [@microsoft/generator-sharepoint](http://aka.ms/spfx). These dependencies need to be updated together.


Updates `ejs` from 2.7.1 to 3.1.10
- [Release notes](https://github.com/mde/ejs/releases)
- [Commits](mde/ejs@v2.7.1...v3.1.10)

Updates `@microsoft/generator-sharepoint` from 1.9.1 to 1.19.0

---
updated-dependencies:
- dependency-name: ejs
  dependency-type: indirect
- dependency-name: "@microsoft/generator-sharepoint"
  dependency-type: direct:development
...

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