Bump slugify from 1.3.1 to 1.3.4

Bumps [slugify](https://github.com/simov/slugify) from 1.3.1 to 1.3.4.
- [Release notes](https://github.com/simov/slugify/releases)
- [Commits](simov/slugify@v1.3.1...v1.3.4)

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

Author: dependabot-support

package-lock.json

@@ -38,7 +38,7 @@
     "react": "^16.5.2",
     "react-dom": "^16.6.1",
     "react-helmet": "^5.2.0",
-    "slugify": "^1.3.1",
+    "slugify": "^1.3.4",
     "string.prototype.includes": "^1.0.0",
     "string.prototype.repeat": "^0.2.0",
     "typography": "^0.16.17"