Bump grunt-shell from 3.0.1 to 4.0.0 (#1207)

Bumps [grunt-shell](https://github.com/sindresorhus/grunt-shell) from 3.0.1 to 4.0.0.
- [Release notes](https://github.com/sindresorhus/grunt-shell/releases)
- [Commits](sindresorhus/grunt-shell@v3.0.1...v4.0.0)

---
updated-dependencies:
- dependency-name: grunt-shell
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

package.json

@@ -35,7 +35,7 @@
     "grunt-contrib-watch": "^1.1.0",
     "grunt-sails-linker": "^1.0.4",
     "grunt-sass": "3.1.0",
-    "grunt-shell": "^3.0.1",
+    "grunt-shell": "^4.0.0",
     "grunt-sync": "^0.8.2",
     "grunt-ts": "^6.0.0-beta.22",
     "har-validator": "5.1.5",