Issue #3317081 by jonathan1055, TR: Add Travis test at 9.5 and fix phpcs installed_paths

.travis.yml

@@ -71,12 +71,8 @@ before_script:
   - travis_retry composer install
 
   # Coder is already installed as part of composer install. For Coder versions
-  # up to 8.3.13 (Core 9.3) we need to set the installed_paths to pick up the
-  # Drupal standards. From 8.3.14 (Core 9.4+) this is done at install time.
-  - |
-    if [[ "$DRUPAL_CORE" == "9.1.x" ]]; then
-      $DRUPAL_ROOT/vendor/bin/phpcs --config-set installed_paths $DRUPAL_ROOT/vendor/drupal/coder/coder_sniffer
-    fi
+  # up to 8.3.13 (Core 9.3) we need to get this extra requirement.
+  - travis_retry composer require slevomat/coding-standard:*
 
   # Start a web server on port 8888, run in the background.
   - php -S localhost:8888 &
@@ -93,6 +89,10 @@ script:
   - ./vendor/bin/phpunit -c ./core/phpunit.xml.dist ./modules/$MODULE/tests/
 
   # Check for coding standards. First show the versions.
+  - composer config --no-plugins allow-plugins.composer/installers true
+  - composer config --no-plugins allow-plugins.dealerdirect/phpcodesniffer-composer-installer true
+  - composer config --no-plugins allow-plugins.drupal/core-project-message true
+  - composer config --no-plugins allow-plugins.drupal/core-vendor-hardening true
   - composer show drupal/coder | egrep 'name |vers'
   - composer show squizlabs/php_codesniffer | egrep 'name |vers'
   - $DRUPAL_ROOT/vendor/bin/phpcs --version