Bump InstUI to version 0.18.2

closes CNVS-33640

Test Plan:
  - Automated tests pass
  - InstUI components currently in Canvas are okay

Change-Id: If36cf170d1b9e75d874c7f482656165e83fb3f85
Reviewed-on: https://gerrit.instructure.com/96610
Tested-by: Jenkins
Reviewed-by: John Corrigan <jcorrigan@instructure.com>
QA-Review: Heath Hales <hhales@instructure.com>
Product-Review: Clay Diffrient <cdiffrient@instructure.com>

package.json

@@ -9,7 +9,7 @@
   "dependencies": {
     "brandable_css": "0.0.67",
     "fullcalendar": "https://github.com/ryankshaw/fullcalendar.git#aa686b36d10cee1e1e3ec7c7784145e46667d47d",
-    "instructure-ui": "0.17.3",
+    "instructure-ui": "0.18.2",
     "instructure-icons": "~0.0.14",
     "tinymce": "4.1.9"
   },