Bump gulp-ejs in /css/css-writing-modes/tools/generators

Bumps [gulp-ejs](https://github.com/rogeriopvl/gulp-ejs) from 1.2.2 to 5.1.0.
- [Release notes](https://github.com/rogeriopvl/gulp-ejs/releases)
- [Changelog](https://github.com/rogeriopvl/gulp-ejs/blob/master/CHANGELOG.md)
- [Commits](rogeriopvl/gulp-ejs@v1.2.2...v5.1.0)

---
updated-dependencies:
- dependency-name: gulp-ejs
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

css/css-writing-modes/tools/generators/package.json

@@ -9,7 +9,7 @@
     "connect": "^3.4.0",
     "ejs": "^2.3.1",
     "gulp": "^3.8.11",
-    "gulp-ejs": "^1.1.0",
+    "gulp-ejs": "^5.1.0",
     "gulp-rename": "^1.2.2",
     "minimist": "^1.1.1",
     "serve-index": "^1.7.2",