Bump open from 0.0.5 to 6.0.0

Bumps [open](https://github.com/sindresorhus/open) from 0.0.5 to 6.0.0.
- [Release notes](https://github.com/sindresorhus/open/releases)
- [Commits](https://github.com/sindresorhus/open/commits/v6.0.0)

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

package.json

@@ -70,7 +70,7 @@
     "minimatch": "^3.0.4",
     "modernizr": "^3.6.0",
     "node-sass": "^4.11.0",
-    "open": "0.0.5",
+    "open": "6.0.0",
     "path": "^0.12.7",
     "plugin-error": "^1.0.1",
     "postcss-loader": "^3.0.0",