build(deps-dev): update @stencil/core requirement from ^0.11.0 to ^0.…

…12.4 in /packages/@ionic/lab (#3554)

Updates the requirements on [@stencil/core](https://github.com/ionic-team/stencil) to permit the latest version.
- [Release notes](https://github.com/ionic-team/stencil/releases)
- [Changelog](https://github.com/ionic-team/stencil/blob/master/CHANGELOG.md)
- [Commits](https://github.com/ionic-team/stencil/commits/v0.12.4)

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

packages/@ionic/lab/package.json

@@ -53,7 +53,7 @@
     "tslib": "^1.9.0"
   },
   "devDependencies": {
-    "@stencil/core": "^0.11.0",
+    "@stencil/core": "^0.12.4",
     "@stencil/dev-server": "0.0.18",
     "@types/express": "^4.11.0",
     "@types/node": "^6.0.101",