add phpstan

.github/workflows/php-cs-fixer.yaml

@@ -0,0 +1,18 @@
+name: "Linter: PHP"
+
+on:
+  pull_request:
+    paths:
+      - '**.php'
+
+jobs:
+  php-cs-fixer:
+    runs-on: ubuntu-20.04
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: PHP-CS-Fixer
+        uses: docker://oskarstark/php-cs-fixer-ga
+        with:
+          args: --dry-run

.github/workflows/phpstan.yaml

@@ -0,0 +1,30 @@
+name: Static analysis - phpstan
+
+on:
+  pull_request:
+    paths:
+      - '**.php'
+
+jobs:
+  phpstan:
+    runs-on: ubuntu-20.04
+
+    steps:
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: '8.0'
+          extensions: "json,memcached"
+          ini-values: "memory_limit=-1"
+          coverage: none
+
+      - name: Checkout target branch
+        uses: actions/checkout@v2
+
+      - name: 'Install project dependencies'
+        run: |
+          composer update --no-interaction --prefer-dist --optimize-autoloader --prefer-stable
+
+      - name: phpstan
+        run: |
+          ./vendor/bin/phpstan --no-interaction --no-progress

.github/workflows/phpunit.yaml

@@ -40,10 +40,17 @@ jobs:
             php-version: "8.0"
             deps: "normal"
 
+          - symfony-require: "5.4.*"
+            php-version: "8.1"
+            deps: "normal"
+
           - symfony-require: "6.0.*"
             php-version: "8.0"
-            deps: "dev"
+            deps: "normal"
 
+          - symfony-require: "6.0.*"
+            php-version: "8.1"
+            deps: "normal"
 
       fail-fast: true