Import paper-dialog, paper-dialog-behavior and paper-dialog-scrollable

Change-Id: I1c43d78e3d785a60c8930fabbe5ca8e38573483a
diff --git a/polygerrit-ui/app/package.json b/polygerrit-ui/app/package.json
index 06e2764..491920d 100644
--- a/polygerrit-ui/app/package.json
+++ b/polygerrit-ui/app/package.json
@@ -14,6 +14,9 @@
     "@polymer/iron-overlay-behavior": "^3.0.2",
     "@polymer/iron-selector": "^3.0.1",
     "@polymer/paper-button": "^3.0.1",
+    "@polymer/paper-dialog": "^3.0.1",
+    "@polymer/paper-dialog-behavior": "^3.0.1",
+    "@polymer/paper-dialog-scrollable": "^3.0.1",
     "@polymer/paper-input": "^3.0.2",
     "@polymer/paper-item": "^3.0.1",
     "@polymer/paper-listbox": "^3.0.1",