Remove reduntant role attribute

See:
* https://github.com/alphagov/govuk-frontend/releases/tag/v5.3.0
* alphagov/govuk-frontend#4854

Note that the 'region' role has not been removed in the few places where it is
currently used as they are not in section tags.

app/views/grape_swagger_rails/application/index.html.haml

@@ -64,7 +64,7 @@
     = govuk_skip_link_to(t('layouts.skip_content'), '#main-content')
 
     - unless @omit_header
-      %header.govuk-header.with-proposition{ role: 'banner', data: { module: 'govuk-header' } }
+      %header.govuk-header.with-proposition{ data: { module: 'govuk-header' } }
         .govuk-header__container.govuk-width-container
           .govuk-header__logo
             = render 'layouts/govuk_logo'
@@ -85,7 +85,7 @@
                     = govuk_header_link_to t('layouts.user.sign_out'), '/users/sign_out', method: :delete
 
     .govuk-width-container
-      %main#main-content.govuk-main-wrapper{ role: 'main' }
+      %main#main-content.govuk-main-wrapper
         #message-bar.swagger-ui-wrap
 
         #swagger-ui-container.swagger-ui-wrap
@@ -96,7 +96,7 @@
 
     -# = render partial: 'layouts/footer'
     -# renderd partial err: undefined local variable or method `contact_us_page_path'
-    %footer.govuk-footer{ role: 'contentinfo' }
+    %footer.govuk-footer
       .govuk-width-container
         .govuk-footer__meta
           .govuk-footer__meta-item.govuk-footer__meta-item--grow

app/views/layouts/_footer.html.haml

@@ -1,4 +1,4 @@
-%footer.govuk-footer{ role: 'contentinfo' }
+%footer.govuk-footer
   .govuk-width-container
     .govuk-footer__meta
       .govuk-footer__meta-item.govuk-footer__meta-item--grow

app/views/layouts/application.html.haml

@@ -35,7 +35,7 @@
       %noscript
         %iframe{ src: "https://www.googletagmanager.com/ns.html?id=#{ENV['GTM_TRACKER_ID']}", style: 'display: none; visibility: hidden', height: '0', width: '0' }
 
-    %header.govuk-header.with-proposition{ role: 'banner', data: { module: 'govuk-header' } }
+    %header.govuk-header.with-proposition{ data: { module: 'govuk-header' } }
       .govuk-header__container.govuk-width-container
         .govuk-header__logo
           = render 'layouts/govuk_logo'
@@ -50,7 +50,7 @@
 
       = render partial: 'layouts/primary_navigation'
 
-      %main#main-content.govuk-main-wrapper{ role: 'main' }
+      %main#main-content.govuk-main-wrapper
         .govuk-grid-row
           .govuk-grid-column-two-thirds
             = render partial: 'shared/downtime_warning'

app/views/pages/api_landing.html.haml

@@ -159,7 +159,7 @@
           %h2#parent-subsection.govuk-heading-m
             = "Table of contents"
 
-          %nav{ role: 'navigation', 'aria-labelledby': 'parent-subsection' }
+          %nav{ 'aria-labelledby': 'parent-subsection' }
             %ul.govuk-list.govuk-list--spaced
               %li
                 = govuk_link_to 'Overview', '#overview'