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/viewer/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@ohif/viewer",
-  "version": "2.0.0",
+  "version": "2.1.0",
   "description": "OHIF Viewer",
   "author": "OHIF Contributors",
   "license": "MIT",
@@ -45,14 +45,14 @@
   },
   "dependencies": {
     "@babel/runtime": "^7.5.5",
-    "@ohif/core": "^1.5.2",
+    "@ohif/core": "^1.6.0",
     "@ohif/extension-cornerstone": "^2.0.0",
     "@ohif/extension-dicom-html": "^1.0.0",
     "@ohif/extension-dicom-microscopy": "^0.50.6",
     "@ohif/extension-dicom-pdf": "^1.0.0",
-    "@ohif/extension-vtk": "^0.52.20",
+    "@ohif/extension-vtk": "^0.52.21",
     "@ohif/i18n": "^0.51.0",
-    "@ohif/ui": "^0.56.1",
+    "@ohif/ui": "^0.57.0",
     "@tanem/react-nprogress": "^1.1.25",
     "classnames": "^2.2.6",
     "core-js": "^3.2.1",