Update language for gradebook update alert and add i18n

closes TALLY-285

test plan
-run server with 'lolcalization=true'
-create a course with new gradebook feature flag turned off
-navigate to the gradebook
-ensure the alert at the top of the page, including the message
and the link text is localized


Change-Id: I63927d9a3c3d997b9010a7e0fd58867f66920cf9
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/217128
Reviewed-by: Keith Garner <kgarner@instructure.com>
Reviewed-by: Spencer Olson <solson@instructure.com>
Reviewed-by: Adrian Packel <apackel@instructure.com>
Reviewed-by: Gary Mei <gmei@instructure.com>
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Tested-by: Jenkins
QA-Review: Robin Kuss <rkuss@instructure.com>
Product-Review: Jonathan Fenton <jfenton@instructure.com>

app/jsx/bundles/gradebook.js

@@ -17,6 +17,7 @@
  */
 
 import $ from 'jquery'
+import I18n from 'i18n!gradebook'
 import {Alert} from '@instructure/ui-alerts'
 import Backbone from 'Backbone'
 import {Link, Text} from '@instructure/ui-elements'
@@ -75,9 +76,11 @@ const GradebookRouter = Backbone.Router.extend({
     ReactDOM.render(
       <Alert variant="warning">
         <Text>
-          This version of Gradebook is being replaced by an updated Gradebook on January 18, 2020.
+          {I18n.t(
+            'This version of Gradebook is being replaced by an updated Gradebook on or before January 18, 2020.'
+          )}
           <Link href={newGradebookInfoURL} margin="0 xx-small">
-            Learn More
+            {I18n.t('Learn More')}
           </Link>
         </Text>
       </Alert>,