Merge branch '5.4' into 6.0

* 5.4:
  [DI] add missing linter exception
  [ci] allow flex to run in CI

Author: javiereguiluz

.doctor-rst.yaml

@@ -91,6 +91,7 @@ whitelist:
         - '.. versionadded:: 1.8' # MakerBundle
         - '.. versionadded:: 1.18' # Flex in setup/upgrade_minor.rst
         - '.. versionadded:: 1.0.0' # Encore
+        - '.. versionadded:: 5.1' # Private Services
         - '0 => 123' # assertion for var_dumper - components/var_dumper.rst
         - '1 => "foo"' # assertion for var_dumper - components/var_dumper.rst
         - '123,' # assertion for var_dumper - components/var_dumper.rst

.github/workflows/ci.yaml

@@ -116,6 +116,11 @@ jobs:
             if: ${{ steps.find-files.outputs.files }}
             run: composer create-project symfony-tools/code-block-checker:@dev _checker
 
+          - name: Allow Flex
+            if: ${{ steps.find-files.outputs.files }}
+            run: |
+              composer config --no-plugins allow-plugins.symfony/flex true
+
           - name: Install test application
             if: ${{ steps.find-files.outputs.files }}
             run: |