build(deps-dev): bump open from 0.0.5 to 6.0.0 in /uaa/slate

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)

---
updated-dependencies:
- dependency-name: open
  dependency-type: direct:development
...

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

uaa/slate/package.json

@@ -131,7 +131,7 @@
     "object-assign": "^4.0.1",
     "on-finished": "^2.3.0",
     "once": "^1.3.3",
-    "open": "0.0.5",
+    "open": "6.0.0",
     "orchestrator": "^0.3.7",
     "ordered-read-streams": "^0.3.0",
     "os-homedir": "^1.0.1",