Add lint action

.github/workflows/lint.yaml

@@ -0,0 +1,79 @@
+# DO NOT EDIT THIS FILE!
+#
+# It's auto-generated by sonata-project/dev-kit package.
+
+name: Lint
+
+on:
+    push:
+        branches:
+            - 1.x
+            - master
+    pull_request:
+
+env:
+    ACTIONS_ALLOW_UNSECURE_COMMANDS: true
+
+jobs:
+    php-cs-fixer:
+        name: PHP-CS-Fixer
+
+        runs-on: ubuntu-latest
+
+        steps:
+            - name: Checkout
+              uses: actions/checkout@v2
+
+            - name: Run PHP-CS-Fixer
+              uses: docker://oskarstark/php-cs-fixer-ga:2.18.1
+              with:
+                  args: --ansi --verbose --diff --dry-run
+
+    composer-normalize:
+        name: composer-normalize
+
+        runs-on: ubuntu-latest
+
+        steps:
+            - name: Checkout
+              uses: actions/checkout@v2
+
+            - name: Run composer-normalize
+              uses: docker://ergebnis/composer-normalize-action:0.8.0
+              with:
+                  args: --dry-run
+
+    yaml-files:
+        name: YAML files
+
+        runs-on: ubuntu-latest
+
+        steps:
+            - name: Checkout
+              uses: actions/checkout@v2
+
+            - name: Install Ruby 2.6
+              uses: actions/setup-ruby@v1
+              with:
+                  ruby-version: '2.6'
+
+            - name: Install required gem
+              run: gem install yaml-lint
+
+            - name: Lint files
+              run: make lint-yaml
+
+    xml-files:
+        name: XML files
+
+        runs-on: ubuntu-latest
+
+        steps:
+            - name: Checkout
+              uses: actions/checkout@v2
+
+            - name: Install required dependencies
+              run: sudo apt-get update && sudo apt-get install libxml2-utils
+
+            - name: Lint files
+              run: make lint-xml