chore(release): publish [skip ci]

- @ohif/extension-cornerstone@1.4.0
 - @ohif/extension-vtk@0.52.21
 - @ohif/core@1.6.0
 - @ohif/ui@0.57.0
 - @ohif/viewer@2.1.0

platform/core/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@ohif/core",
-  "version": "1.5.2",
+  "version": "1.6.0",
   "description": "Generic business logic for web-based medical imaging applications",
   "author": "OHIF Core Team",
   "license": "MIT",