chore(deps-dev): bump node-sass in /examples/sapper-rollup (#240)

Bumps [node-sass](https://github.com/sass/node-sass) from 4.13.0 to 4.13.1.
- [Release notes](https://github.com/sass/node-sass/releases)
- [Changelog](https://github.com/sass/node-sass/blob/master/CHANGELOG.md)
- [Commits](sass/node-sass@v4.13.0...v4.13.1)

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

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

Author: dependabot[bot]

Diff for: examples/sapper-rollup/package-lock.json

@@ -22,7 +22,7 @@
     "@babel/plugin-transform-runtime": "^7.6.2",
     "@babel/preset-env": "^7.6.3",
     "@babel/runtime": "^7.6.3",
-    "node-sass": "^4.13.0",
+    "node-sass": "^4.13.1",
     "npm-run-all": "^4.1.5",
     "pug": "^2.0.4",
     "rollup": "^1.26.0",