Issue #2033653 by damiankloip: Remove occurrences of api_version()

core/modules/entity_reference/tests/modules/entity_reference_test/config/views.view.test_entity_reference.yml

-api_version: '3.0'
 base_field: nid
 base_table: node
 core: 8.x

core/modules/views/config/schema/views.schema.yml

@@ -7,8 +7,6 @@ views.view.*:
     status:
       type: boolean
       label: 'Status'
-    api_version:
-      label: 'API version'
     module:
       label: 'Module'
     name:

core/modules/views/tests/modules/views_test_config/test_views/views.view.test_display_invalid.yml

-api_version: '3.0'
 base_table: node
 core: '8'
 description: ''

core/modules/views/tests/modules/views_test_config/test_views/views.view.test_mini_pager.yml

@@ -4,7 +4,6 @@ description: ''
 tag: ''
 label: test_mini_pager
 core: 8.x
-api_version: '3.0'
 display:
   default:
     display_plugin: default