Add basic phpstan level 1 config/ci

Author: Seldaek

.github/workflows/phpstan.yml

@@ -0,0 +1,34 @@
+name: "PHPStan"
+
+on:
+  - push
+  - pull_request
+
+env:
+  COMPOSER_FLAGS: "--ansi --no-interaction --no-progress --prefer-dist"
+
+jobs:
+  tests:
+    name: "PHPStan"
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: "Checkout"
+        uses: "actions/checkout@v2"
+
+      - name: "Install PHP"
+        uses: "shivammathur/setup-php@v2"
+        with:
+          coverage: "none"
+          extensions: "intl, zip"
+          ini-values: "memory_limit=-1"
+          php-version: "7.4"
+
+      - name: "Update dependencies"
+        run: "composer update ${{ env.COMPOSER_FLAGS }}"
+
+      - name: Run PHPStan
+        run: |
+          composer require --dev phpstan/phpstan:^0.12.93 marc-mabe/php-enum-phpstan ${{ env.COMPOSER_FLAGS }}
+          vendor/bin/phpstan analyse

phpstan.neon

@@ -0,0 +1,8 @@
+parameters:
+    level: 1
+    paths:
+        - ./src/
+    ignoreErrors: []
+
+includes:
+    - vendor/marc-mabe/php-enum-phpstan/extension.neon