[ci] we do not need to install flex globally anymore

Author: jrushlow

.github/workflows/ci.yaml

@@ -135,9 +135,6 @@ jobs:
             - name: "Add PHPUnit matcher"
               run: echo "::add-matcher::${{ runner.tool_cache }}/phpunit.json"
 
-            - name: "Require symfony/flex"
-              run: composer global require --no-progress --no-scripts --no-plugins symfony/flex
-
             - name: "Composer install"
               uses: "ramsey/composer-install@v1"
               with:

appveyor.yml

@@ -53,7 +53,6 @@ install:
     - del composer.phar
     - rename composer-stable.phar composer.phar
     - cd C:\projects\maker-bundle
-    - composer global require --no-progress --no-scripts --no-plugins symfony/flex
     - IF %dependencies%==highest appveyor-retry composer update --no-progress --no-suggest --ansi
     - composer install --no-interaction --no-progress --ansi --no-scripts --working-dir=tools/twigcs
     - composer install --no-interaction --no-progress --ansi --no-scripts --working-dir=tools/php-cs-fixer