Issue #3111394 by heddn: Restore core key, or update version requirement

migrate_example/migrate_example.info.yml

@@ -2,6 +2,7 @@ type: module
 name: Migrate Example
 description: 'Examples of how Drupal 8+ migration compares to previous versions.'
 package: Examples
+core: 8.x
 core_version_requirement: ^8 || ^9
 dependencies:
   - drupal:migrate

migrate_example/migrate_example_setup/migrate_example_setup.info.yml

@@ -2,6 +2,7 @@ type: module
 name: Migrate Example Setup
 description: 'Separate site configuration for the example from the actual migration.'
 package: Migration
+core: 8.x
 core_version_requirement: ^8 || ^9
 hidden: true
 dependencies:

migrate_example_advanced/migrate_example_advanced.info.yml

@@ -2,6 +2,7 @@ type: module
 name: Migrate Example (Advanced)
 description: 'Specialized examples of Drupal 8+ migration.'
 package: Examples
+core: 8.x
 core_version_requirement: ^8 || ^9
 dependencies:
   - drupal:migrate

migrate_example_advanced/migrate_example_advanced_setup/migrate_example_advanced_setup.info.yml

@@ -2,6 +2,7 @@ type: module
 name: Migrate Advanced Example Setup
 description: 'Separate site configuration for the example from the actual migration.'
 package: Migration
+core: 8.x
 core_version_requirement: ^8 || ^9
 hidden: true
 dependencies:

migrate_json_example/migrate_json_example.info.yml

@@ -2,6 +2,7 @@ type: module
 name: Migrate JSON Example
 description: 'Simple JSON Migration example'
 package: Examples
+core: 8.x
 core_version_requirement: ^8 || ^9
 dependencies:
   - drupal:migrate

migrate_plus.info.yml

@@ -2,6 +2,7 @@ type: module
 name: Migrate Plus
 description: 'Enhancements to core migration support'
 package: Migration
+core: 8.x
 core_version_requirement: ^8 || ^9
 dependencies:
   - drupal:migrate

tests/modules/migrate_plus_test/migrate_plus_test.info.yml

@@ -2,6 +2,7 @@ type: module
 name: Migrate Plus Test
 description: 'Test module to test Migrate Plus.'
 package: Testing
+core: 8.x
 core_version_requirement: ^8 || ^9
 dependencies:
   - drupal:migrate